Husqvarna Chainsaw 1018855 26 Manual
Husqvarna Chain Saws  
Workshop Manual  
101 88 55-26  
LIST OF CONTENTS  
Introduction ..................................... 3  
Safety regulations ........................... 5  
Technical Data ................................. 6  
Tools ............................................... 14  
Service data ................................... 20  
Trouble shooting ........................... 40  
Safety equipment .......................... 42  
Starter............................................. 57  
Electrical system ........................... 61  
Centrifugal clutch.......................... 67  
Lubrication system ....................... 70  
Carburettor..................................... 83  
Air filter ........................................ 101  
Tank unit....................................... 103  
Anti-vibration system.................. 106  
Piston cylinder............................. 108  
Crankcase and crankshaft.......... 114  
2– English  
INTRODUCTION  
General  
Updates  
As production continues, changes will be intro-  
duced successively to the chain saw. If at any  
time these changes influence service and/or  
spares, special service announcements will be  
sent out, which means that this manual will cease  
to be current with time. In order to avoid prob-  
lems, the manual should always be read together  
with all service announcements that apply to the  
specific model of chain saw.  
This workshop manual provides a detailed de-  
scription of procedures for trouble shooting, repair  
and testing of the chain saws. Safety precautions  
that should be taken during repair are also  
described.  
This workshop manual applies to the engine  
assembly in the following chain saws:  
257  
262XP  
268  
36  
40  
Tools  
41  
42  
For specific procedures special tools are re-  
quired. In this workshop manual, all the service  
tools required are listed. Use of the tools is  
described in appropriate sections.  
272XP  
268K  
272K  
272S  
45  
51  
55  
61  
Always use Husqvarna original:  
281XP  
288XP  
•
•
•
Spare parts  
Service tools  
Accessories  
242XP  
246  
394XP  
3120XP  
254XP  
Layout  
Safety  
The descriptive sections in this workshop manual  
are set out in a number of flow diagrams. When  
carrying out repairs on a specific chain saw,  
follow the signs that apply to the saw in question.  
Note!  
The section dealing with safety should be  
read and understood by all who carry out  
repair or service work on the chain saw.  
Diagrams are not numbered as they are linked to  
the actual text, either by lines or by being in the  
same box.  
There are warning symbols on the chain saw. If a  
warning symbol has been damaged or is missing,  
it must be replaced immediately in order to  
maximise safety when the saw is in use.  
Positional directives to components inside the  
diagrams are designated with A, B, etc. and start  
from A again in each new section.  
Target group  
This workshop manual is written for personnel  
that are assumed to have general knowledge of  
service and repair of small engines.  
The workshop manual should be read and under-  
stood by all personnel carrying out service and  
repair work on the chain saw. The manual is also  
suitable for use in the training of new employees.  
English – 3  
INTRODUCTION  
Use  
Dismantling and reassembly of the entire  
chain saw  
This workshop manual can be used in two different  
ways:  
When the entire chain saw is to be dismantled  
and reassembled, proceed as follows:  
•
•
Repair of a specific sub-assembly  
Dismantling and reassembly of the entire chain  
saw  
1. Refer to page 57, which deals with the  
Starter and carry out the instructions  
under the heading Dismantling.  
Repair of a specific sub-assembly  
2. Work forwards through the manual and  
carry out Dismantling instructions in the  
order that the sections occur.  
When a specific sub-assembly on the chain saw is  
to be repaired, proceed as follows:  
1. Refer to the page referring to the relevant sub-  
assembly.  
3. Return to the Starter on page 58 and  
follow the instructions under Cleaning  
and Inspection.  
2. Carry out the steps: Dismantling  
Cleaning and inspection  
Reassembly  
4. Work forward through the manual and  
carry out Cleaning and Inspection in the  
order that the sections occur.  
5. Order or collect all the required spare  
parts from the spare parts stores.  
6. In order to Assemble the chain saw,  
proceed as follows:  
•
•
•
•
Refer to pages 117-120 which deals with  
the Crankcase and carry out the instruc-  
tions under Assembly.  
Refer to pages 111-112 which deals with  
the Piston and Cylinder and carry out  
the instructions under Assembly.  
Refer to pages 107 which deals with the  
Anti-vibration system and carry out the  
instructions under Assembly.  
Refer to page 105 which deals with the  
Tank unit and carry out the instructions  
under Assembly.  
Continue to work backwards through the  
manual and carry out Assembly instructions  
as the sections occur.  
In order to improve understanding, some  
sections begin with a Description of the  
relevant sub-assembly.  
4– English  
SAFETY REGULATIONS  
Special instructions  
General Instructions  
Workshops where chain saws are serviced  
must be equipped with safety equipment  
as set out in local directives.  
The fuel used in the chain saw poses the  
following hazards:  
1. The fluid and its fumes are poisonous.  
2. Can cause eye and skin irritation.  
3. Can cause breathing difficulties  
4. Is highly inflammable.  
No one should repair a chain saw without  
first having read and understood the  
contents of this workshop manual.  
The bar, chain and clutch cover (chain  
brake) must be assembled before the  
chain saw is started, otherwise the clutch  
may come loose causing personal injury.  
The following warning texts are to be found  
in this manual in certain places. The  
warning texts occur before the procedure  
to which they refer.  
Wear ear muffs when testing the chain  
saw.  
Do not use the saw until it has been  
adjusted so that the chain does not rotate  
when idling.  
WARNING!  
The warning text indicates a risk  
!
of personal injury if instructions  
are not followed.  
Bear in mind the fire risk. The saw can  
produce sparks that can cause a fire hazard..  
After testing, do not touch the  
silencer until it has cooled. Risk  
of burns. This especially applies if  
NOTE!  
The warning text indicates a risk of  
damage to equipment if instructions  
are not followed.  
1
the saw is fitted with a catalytic converter.  
The coating on and in the catalytic element  
is hazardous to touch. Use protective gloves  
when working on the catalytic converter.  
The chain saw is type approved with  
regard to safety according to applicable  
legal requirements when fitted with the  
cutting equipment specified in the  
Inadequate chain lubrication can result in  
the chain breaking, which can cause  
serious or fatal injury.  
Operator's Manual. Equipping the saw with  
other equipment or accessories and spare  
parts not approved by Husqvarna can  
result in non compliance with these safety  
requirements and liability for persons  
carrying out such modifications.  
Make sure that the starter recoil  
spring does not fly out and cause  
personal injury. Release the spring  
tension before the cord pulley is removed.  
When removing the pressure  
spring for the chain brake, ensure  
that the brake is in the 'on'  
position which reduces the spring  
tension, otherwise the spring can fly out  
causing personal injury.  
After repair, the chain brake must be  
checked in accordance with the  
instructions on page 47.  
When replacing the crankshaft bearings  
note that the crankcase halves are hot.  
Use protective gloves.  
When using compressed air, the air jet  
should never be pointed towards the body.  
Air can be forced into the blood stream,  
which can cause fatality.  
English – 5  
TECHNICAL DATA  
Displacement  
cm3  
Bore  
mm  
Stroke  
mm  
Max. power at  
r/min  
36  
40  
41  
36  
40  
40  
38.0  
40.0  
40.0  
32.0  
32.0  
32.0  
9000  
9000  
9000  
42  
45  
51  
42  
44  
51  
42.0  
42.0  
45.0  
30.0  
32.0  
32.0  
9300  
9000  
9000  
Spark plug gap  
mm/inches  
Ignition system  
Air gap  
Carburettor  
mm/inches  
36  
40  
41  
0.5/ .02  
0.5/ .02  
0.5/ .02  
PHELON  
PHELON  
PHELON  
0.3/ .012  
0.3/ .012  
0.3/ .012  
WALBRO WT 239  
ZAMA C1Q-EL1  
WALBRO WT 239  
42  
45  
51  
0.5/ .02  
0.5/ .02  
0.5/ .02  
SEM AM 7  
PHELON  
ELECTROLUX ET  
0.3/ .012  
0.3/ .012  
0.3/ .012  
WALBRO HDA 98  
ZAMA C1Q-EL1  
WALBRO WT 170  
Bar length  
cm/inches  
Chain speed  
m/s  
Chain pitch  
inches  
Drive link gauge  
mm/inches  
36  
40  
41  
33-46/13-18  
33-46/13-18  
33-46/13-18  
17.3/9000 rpm  
17.4/8500 rpm  
17.3/9000 rpm  
.325-3/8  
.325  
.325-3/8  
1.3/ .050  
1.3/ .050  
1.3/ .050  
42  
45  
51  
28-46/11-18  
33-46/13-18  
33-51/13-20  
17.9/9300 rpm  
17.4/8500 rpm  
17.4/9000 rpm  
.325  
.325  
.325-3/8  
1.5/ .058 / 1.3/ .0501)  
1.3/ .050  
1.5/ .058 / 1.3/ .0501)  
1) From May 1996  
6– English  
TECHNICAL DATA  
Idling speed  
r/min  
Engagement speed  
r/min  
Max. speed  
r/min  
Spark plug  
Champion  
36  
40  
41  
3000  
2500  
3000  
4500  
3600  
4500  
13000  
12500  
13000  
RCJ 7 Y  
RCJ 7 Y  
RCJ 7 Y  
42  
45  
51  
2700  
2500  
2500  
3800  
3600  
3700  
14500  
12500  
12500  
RCJ 7 Y  
RCJ 7 Y  
RCJ 7 Y  
Fuel tank volume  
Litres  
Oil pump capacity  
cm3/min at 8.500 rpm  
Oil tank volume  
Litres  
Automatic oil pump  
36  
40  
41  
0.4  
0.5  
0.4  
7
8
7
0.2  
0.25  
0.2  
Yes  
Yes  
Yes  
42  
45  
51  
0.5  
0.5  
0.6  
3-7  
8
10  
0.27  
0.25  
0.3  
Yes  
Yes  
Yes  
Weight without bar and chain  
kg  
Weight with bar and chain  
kg/lbs  
Handle heater  
Watt/ r/min  
36  
40  
41  
4.6  
4.7  
4.6  
5.3 (13")  
5.4 (13")  
5.3 (13")  
No  
No  
No  
42  
45  
51  
4.7  
4.7  
5.2  
5.5 (13")  
5.4 (13")  
6.2 (15")  
No  
No  
No  
English – 7  
TECHNICAL DATA  
Displacement  
cm3  
Bore  
mm  
Stroke  
mm  
Max. power at  
r/min  
55  
61  
242XP  
53  
62  
42  
46.0  
48.0  
42.0  
32.0  
34.0  
30.0  
9000  
8300  
9900  
246  
254XP  
257  
46  
54  
57  
44.0  
45.0  
46.0  
30.0  
34.0  
34.0  
9000  
9300  
9000  
Spark plug gap  
mm/inches  
Ignition system  
Air gap  
Carburettor  
mm/inches  
55  
61  
242XP  
0.5/ .02  
0.5/ .02  
0.5/ .02  
ELECTROLUX ET  
ELECTROLUX ET  
SEM AM 7  
0.3/ .012  
0.3/ .012  
0.3/ .012  
WALBRO WT 170  
TILLOTSON HS 254  
WALBRO HDA 98  
246  
254XP  
257  
0.5/ .02  
0.5/ .02  
0.5/ .02  
SEM AM 7  
ELECTROLUX ET  
ELECTROLUX ET  
0.3/ .012  
0.3/ .012  
0.3/ .012  
WALBRO HDA 98  
WALBRO HDA 35B  
WALBRO HDA 120  
Bar length  
cm/inches  
Chain speed  
m/s  
Chain pitch  
inches  
Drive link gauge  
mm/inches  
55  
61  
242XP  
38-51/15-20  
38-51/15-20  
28-46/11-18  
17.4/9000 rpm  
18.4/8300 rpm  
19.1/9900 rpm  
.325-3/8  
3/8  
.325  
1.5/ .058 / 1.3/ .050 1)  
1.5/ .058  
1.5/ .058 / 1.3/ .050 1)  
246  
254XP  
257  
28-46/11-18  
33-51/13-20  
33-51/13-20  
17.3/9000 rpm  
17.3/9300 rpm  
17.3/9000 rpm  
.325  
.325-3/8  
.325-3/8  
1.5/ .058 / 1.3/ .050 1)  
1.5/ .058  
1.5/ .058  
1) From May 1996  
8– English  
TECHNICAL DATA  
Idling speed  
r/min  
Engagement speed  
r/min  
Max. speed  
r/min  
Spark plug  
Champion  
55  
61  
242XP  
2500  
2500  
2700  
3700  
3700  
3900  
12500  
12000  
15500  
RCJ 7 Y  
RCJ 7 Y  
RCJ 7 Y  
246  
254XP  
257  
2700  
2700  
2700  
3900  
3700  
3700  
15000  
13800  
13500  
RCJ 7 Y  
RCJ 7 Y  
RCJ 7 Y  
Fuel tank volume  
Litres  
Oil pump capacity  
cm3/min at 8.500 rpm  
Oil tank volume  
Litres  
Automatic oil pump  
55  
61  
242XP  
0.6  
0.75  
0.5  
10  
4/8/12/17  
3-7  
0.3  
0.45  
0.27  
Yes  
Yes  
Yes  
246  
254XP  
257  
0.5  
0.6  
0.6  
3-7  
3-10  
3-10  
0.27  
0.3  
0.3  
Yes  
Yes  
Yes  
Weight without bar and chain  
kg  
Weight with bar and chain Handle heater  
kg/lbs  
Watt/ r/min  
55  
61  
242XP  
5.2  
6.1  
4.7  
6.2 (15")  
7.1 (15")  
5.5 (13")  
No  
No  
65/10.000  
246  
254XP  
257  
4.7  
5.4  
5.6  
5.5 (13")  
6.3 (13")  
6.6 (13")  
No  
65/10000  
65/10000  
English – 9  
TECHNICAL DATA  
Displacemennt  
cm3  
Bore  
mm  
Stroke  
mm  
Max. power at  
r/min  
262XP  
268  
272XP  
62  
67  
72  
48.0  
50.0  
52.0  
34.0  
34.0  
34.0  
9600  
9000  
9300  
268K  
272K  
272S  
67  
72  
72  
50.0  
52.0  
52.0  
34.0  
34.0  
34.0  
9000  
9300  
9300  
Spark plug gap  
mm/inches  
Ignition system  
Air gap  
Carburettor  
mm/inches  
262XP  
268  
272XP  
0.5/ .02  
0.5/ .02  
0.5/ .02  
ELECTROLUX ET  
ELECTROLUX ET  
ELECTROLUX ET  
0.3/ .012  
0.3/ .012  
0.3/ .012  
WALBRO HDA 120  
TILLOTSON HS 260  
TILLOTSON HS 260  
268K  
272K  
272S  
0.5/ .02  
0.5/ .02  
0.5/ .02  
ELECTROLUX ET  
ELECTROLUX ET  
ELECTROLUX ET  
0.3/ .012  
0.3/ .012  
0.3/ .012  
TILLOTSON HS 255  
TILLOTSON HS 255  
TILLOTSON HS 255  
Bar length  
cm/inches  
Chain speed  
m/s  
Chain pitch  
inches  
Drive link gauge  
mm/inches  
262XP  
268  
272XP  
33-51/13-20  
38-51/15-20  
38-51/15-20  
18.5/9600 rpm  
18.4/9000 rpm  
20.0/9300 rpm  
.325-3/8  
3/8  
3/8  
1.5/ .058  
1.5/ .058  
1.5/ .058  
268K  
272K  
272S  
-
-
-
-
-
-
-
-
-
-
-
-
10– English  
TECHNICAL DATA  
Idling speed  
r/min  
Engagement speed  
r/min  
Max. speed  
r/min  
Spark plug  
Champion  
262XP  
268  
272XP  
2700  
2500  
2500  
3400  
3500  
3500  
13500  
12500  
13500  
RCJ 7 Y  
RCJ 7 Y  
RCJ 7 Y  
268K  
272K  
272S  
2500  
2500  
2500  
3500  
3500  
3500  
10000  
10000  
10000  
RCJ 7 Y  
RCJ 7 Y  
RCJ 7 Y  
Fuel tank volume  
Litres  
Oil pump capacity  
cm3/min at 8.500 rpm  
Oil tank volume  
Litres  
Automatic oil pump  
262XP  
268  
272XP  
0.6  
0.75  
0.75  
6.5-13.5  
4/9/13/17  
5/9/14/19  
0.3  
0.45  
0.45  
Yes  
Yes  
Yes  
268K  
272K  
272S  
0.75  
0.75  
0.75  
-
-
-
-
-
-
-
-
-
Weight without chain and bar  
kg  
Weight with chain and bar Handle heater  
kg/lbs  
Watt/ r/min  
262XP  
268  
272XP  
5.8  
6.2  
6.3  
6.8 (13")  
7.2 (15")  
7.3 (15")  
65/10000  
65/10000  
65/10000  
268K  
272K  
272S  
9.5  
9.6  
-
-
-
-
-
21.0 (including carriage)  
-
English – 11  
TECHNICAL DATA  
Displacement  
cm3  
Bore  
mm  
Stroke  
mm  
Max. power at  
r/min  
281XP  
288XP  
81  
87  
52.0  
54.0  
38.0  
38.0  
9000  
9300  
394XP  
3120XP  
94  
119  
56.0  
60.0  
38.0  
42.0  
8800  
9000  
Spark plug gap  
mm/inches  
Ignition system  
Air gap  
Carburettor  
mm/inches  
281XP  
288XP  
0.5/ .02  
0.5/ .02  
SEM AM 7  
SEM AM 7  
0.3/ .012  
0.3/ .012  
TILLOTSON HS 228  
TILLOTSON HS 228  
394XP  
3120XP  
0.5/ .02  
0.5/ .02  
SEM AM 44  
SEM AM 37  
0.3/ .012  
0.3/ .012  
WALBRO WJ 39  
WALBRO WG 6  
Bar length  
cm/inches  
Chain speed  
m/s  
Chain pitch  
inches  
Drive link gauge  
mm/inches  
281XP  
288XP  
38-71/15-28  
38-71/15-28  
20.0/9000 rpm  
20.7/9300 rpm  
3/8  
3/8  
1.5/ .058  
1.5/ .058  
394XP  
3120XP 60-107/24-42  
46-91/18-36  
19.6/8800 rpm  
20.1/9000 rpm  
3/8-.404  
.404  
1.5/ .058 - 1.6/.063  
1.6/ .063  
12– English  
TECHNICAL DATA  
Idling speed  
r/min  
Engagement speed  
r/min  
Max. speed  
r/min  
Spark plug  
Champion  
281XP  
288XP  
2500  
2500  
3200  
3200  
12500  
12500  
RCJ 6 Y  
RCJ 6 Y  
394XP  
3120XP  
2500  
2500  
3400  
3300  
12500  
11500-12500  
RCJ 6 Y  
RCJ 7 Y  
Fuel tank volume  
Litres  
Oil pump capacity  
cm3/min at 8.500 rpm  
Oil tank volume  
Litres  
Automatic oil pump  
281XP  
288XP  
0.9  
0.9  
9/12/15/18  
9/12/15/18  
0.5  
0.5  
Yes  
Yes  
394XP  
3120XP  
0.9  
1.25  
14-21  
8-51  
0.5  
0.7  
Yes  
Yes  
Weight without bar and chain  
kg  
Weight with bar chain  
kg/lbs  
Handle heater  
Watt/ r/min  
281XP  
288XP  
7.5  
7.5  
8.7 (18")  
8.7 (18")  
56/7200  
56/7200  
394XP  
3120XP  
7.9  
10.4  
9.2 (18")  
12.3 (28")  
65/10000  
No  
English – 13  
TOOLS  
Tools for all chain saws  
502 50 57-01 3/16"  
502 50 16-01 6 mm  
502 50 64-01 5 mm  
502 50 18-01 4 mm  
502 50 19-01 3 mm  
502 50 22-01 8 mm  
502 50 23-01 10 mm  
502 50 88-01 5 mm  
502 50 87-01 4 mm  
502 50 86-01 3 mm  
502 71 13-01  
504 98 26-01  
(36, 41, 40, 45)  
502 50 06-01  
502 51 34-02 (0,3 mm)  
502 51 91-01 (0,5 mm)  
502 50 83-01  
502 50 37-01  
502 70 09-01  
compl 502 50 70-01  
502 51 02-01  
502 71 14-01  
14– English  
TOOLS  
Tools for saws 36 and 41  
Tools for saws 40, 45, 51 and 55  
4 mm  
8 mm  
3 mm; 4 mm; 5 mm  
8 mm; 10 mm  
502 50 33-01  
502 50 33-01  
505 26 79-12  
40 > 910 1116  
45 > 925 1168  
50 > 925 0856  
502 51 94-01  
502 51 94-01  
530 03 11-12  
502 50 99-01  
(55)  
502 50 26-01  
(55)  
505 38 18-17  
(40. 45)  
530 03 11-36  
502 51 00-02  
502 51 61-01  
(51, 55)  
504 90 90-01  
502 50 30-09  
40 > 910 1116  
45 > 925 1168  
502 50 79-01 (55)  
compl 502 50 38-01  
502 54 03-01  
(40, 45, 55)  
502 50 46-01  
(55)  
504 90 29-02  
English – 15  
TOOLS  
Tools for saws 42, 242 and 246  
Tools for saws 254, 257 and 262  
3 mm; 4 mm  
8 mm  
3 mm; 4 mm  
8 mm  
502 50 33-01  
502 50 33-01  
*compl 502 51 49-02  
*compl 502 51  
49-02  
502 51 49-01*  
*502 51 54-01  
502 51 49-01*  
*502 51 54-01  
502 50 26-01*  
502 50 99-01  
502 50 26-01*  
502 50 99-01  
502 70 03-01  
compl 502 50 31-01  
502 51 61-01  
504 90 90-01  
502 51 61-01  
504 90 90-01  
502 50 82-01  
502 51 32-01  
502 50 30-07  
502 51 50-01  
502 50 79-01  
502 50 30-10  
502 51 00-02  
compl 502 50 38-01  
compl 502 50 38-01  
502 50 45-01  
502 50 45-01  
502 50 46-01  
502 50 72-01  
502 50 72-01  
502 50 71-01  
502 50 46-01  
502 50 71-01  
16– English  
TOOLS  
Tools for saws 61, 268 and 272  
Tools for saws 281 and 288  
3 mm; 4 mm; 3/16"  
3 mm; 4 mm; 3/16"  
8 mm  
8 mm  
502 71 36-01 (4 mm)  
502 71 36-01 (4 mm)  
502 50 33-01  
502 50 33-01  
*compl 502 51 49-02  
*compl 502 51 49-02  
502 51 49-01*  
502 51 49-01*  
*502 51 54-01  
*502 51 54-01  
502 50 26-01*  
502 50 26-01*  
502 70 03-01  
compl 502 50 31-01  
502 51 61-01  
504 90 90-01  
502 51 61-01  
504 90 90-01  
502 50 82-01  
502 51 69-01  
(268)  
502 50 30-04  
502 50 30-08  
502 50 53-01  
502 50 66-02  
502 50 52-01  
502 50 67-01  
502 51 00-02  
502 50 66-02  
compl 502 50 38-01  
compl 502 50 38-01  
502 50 45-01  
502 50 46-01  
502 50 47-01  
502 50 47-01  
502 50 81-01  
502 50 46-01  
502 50 48-01  
502 50 20-01  
English – 17  
TOOLS  
Tools for saws 394 and 3120  
3 mm; 4 mm; 5 mm; 3/16"  
8 mm; 10 mm  
502 50 33-01  
*compl 502 51 49-02  
502 51 49-01*  
*502 51 54-01  
502 50 26-01*  
504 90 90-01  
502 50 82-01  
502 50 52-01  
502 50 30-08  
502 50 66-02  
compl 502 50 38-01  
502 52 04-01  
(394)  
502 52 01-01 (394)  
502 71 38-01 (3120)  
502 71 40-01  
(3120)  
502 71 39-01 (394)  
18– English  
TOOLS  
List of tools  
Order number Designation  
Order number  
Designation  
502 51 49-01  
502 51 49-02  
502 51 50-01  
502 51 54-01  
502 51 61-01  
Puller  
Puller  
Socket  
Bolt set  
502 50 06-01  
502 50 16-01  
502 50 18-01  
502 50 19-01  
502 50 20-01  
Pliers  
Allen key  
Allen key  
Allen key  
Assembly tool  
Dismantling tool, crankcase  
502 51 69-01  
502 51 69-01  
502 51 94-01  
502 52 01-01  
502 52 04-01  
Assembly mandrel  
Feeler gauges  
Assembly mandrel  
Cover plate  
502 50 22-01  
502 50 23-01  
502 50 26-01  
502 50 30-04  
502 50 30-08  
Socket  
Socket  
Puller  
Assembly tool  
Assembly tool  
Spacer  
502 54 03-01  
502 70 09-01  
502 71 13-01  
502 71 14-01  
502 71 36-01  
Spacer  
502 50 30-09  
502 50 30-10  
502 50 31-01  
502 50 33-01  
502 50 37-01  
Assembly tool  
Assembly tool  
Puller  
Piston stop  
Vacuum gauge  
Pump blower  
Test spark plug  
Tachometer  
Allen key  
502 71 38-01  
502 71 39-01  
502 71 40-01  
504 90 29-02  
504 90 90-01  
Cover plate  
Cover plate  
Spacer  
Cover plate  
Puller  
502 50 38-01  
502 50 45-01  
502 50 46-01  
502 50 47-01  
502 50 48-01  
Pressure gauge  
Extended socket  
Extended socket  
Cover plate  
Cover plate  
504 98 26-01  
505 26 79-12  
505 38 18-17  
Silicone rubber  
Assembly mandrel  
Puller  
502 50 52-01  
502 50 57-01  
502 50 64-01  
502 50 66-02  
502 50 67-01  
Assembly socket  
Allen key  
Allen key  
U-key  
U-key  
502 50 70-01  
502 50 71-01  
502 50 72-01  
502 50 79-01  
502 50 81-01  
Assembly tool, piston  
Cover plate  
Cover plate  
Assembly mandrel  
Cover plate  
502 50 82-01  
502 50 83-01  
502 50 86-01  
502 50 87-01  
502 50 88-01  
Assembly mandrel  
Hook, tank valve  
Allen key  
Allen key  
Allen key  
502 50 99-01  
502 51 00-02  
502 51 02-01  
502 51 32-01  
502 51 34-02  
Puller sleeve  
U-key  
Assembly fixture  
Assembly sleeve  
Feeler gauge  
English – 19  
SERVICE DATA  
Saws 36 and 41  
●
5
6
10  
15  
●
▲
4
■
●
▲
●
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
20– English  
SERVICE DATA  
6
▲
4
4
●
4
28  
3
English – 21  
SERVICE DATA  
●
Saws 42, 242 and 246  
5
8-10  
7-8  
242  
4-5  
42 246  
15  
5
10  
●
242  
▲
4
▲
■
●
42 246  
8
3
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
●
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
●
22– English  
SERVICE DATA  
2
3
20  
9
13  
▲
▲
2
2
●
2
4
4
28  
9
6
2
English – 23  
SERVICE DATA  
Saws 40 and 45  
●
3-4  
2-3  
7-8  
25-35  
■
●
2-3  
▲
●
▲
●
2
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
24– English  
SERVICE DATA  
2-3  
3-4  
2-3  
2-3  
20  
2-3  
▲
2-3  
2-3  
8-10  
2-3  
●
3-4  
25-30  
English – 25  
SERVICE DATA  
ws 51 and 55  
●
4-5  
7-8  
15  
30-40  
6-8  
■
▲
▲
●
3-4  
3-4  
●
1,5-2  
8-10  
3-4  
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
●
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
●
26– English  
SERVICE DATA  
3-4  
3-4  
3-4  
15  
8-10  
12-14  
▲
3-5  
●
1-2  
25  
3-4  
3-4  
English – 27  
SERVICE DATA  
●
Saws 254 and 257  
254  
5
5
10  
257  
5
10  
15  
35  
4
■
▲
▲
●
8
●
●
3
Character key  
●
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
5
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
3
28– English  
SERVICE DATA  
4
20  
10  
13  
▲
5
4
254  
●
2
3
4
9
28  
5
English – 29  
SERVICE DATA  
Saw 262  
●
5
4
6
10  
15  
4
35  
■
▲
▲
●
8
●
●
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
4
●
4
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
3
30– English  
SERVICE DATA  
2
4
9
20  
13  
▲
5
5
4
4
●
2
3
4
9
28  
5
English – 31  
SERVICE DATA  
Saws 61, 268 and 272  
●
2
10  
6
6
10  
6
35  
▲
5
●
■
▲
268 272  
●
1
4
8
Character key  
Numbers by components that are  
●
bolted refer to the tightening torque in Nm.  
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
3
●
32– English  
SERVICE DATA  
3
1
3
61  
1
3
1
15  
3
10  
268 272  
14  
▲
5
4
6
6
4
●
272  
3
4
3
28  
9
4
English – 33  
SERVICE DATA  
●
Saws 281 and 288  
5
13  
4
6
15  
■
▲
35  
▲
5
●
●
8
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
●
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
6
●
34– English  
SERVICE DATA  
4
3
6
20  
11  
17  
▲
7
7
1
7
3
6
●
4
4
3
35  
7
9
English – 35  
SERVICE DATA  
Saw 394  
●
5
10-12  
6-8  
15  
●
2-4  
▲
■
●
▲
7-9  
●
Character key  
Numbers by components that are  
bolted refer to the tightening torque  
in Nm.  
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
●
36– English  
SERVICE DATA  
5-6  
20-22,5  
3-5  
12-14  
▲
3-5  
5-6  
●
4-5  
30-40  
2-3  
English – 37  
SERVICE DATA  
4
5
38  
▲
■
▲
5
●
3
1
●
8
7
●
5
5
7
Character key  
Numbers by components that are bolted  
refer to the tightening torque in Nm.  
8
▲ = Lubricate using two-stroke oil.  
■ = Lubricate using saw chain oil.  
● = Lubricate using grease.  
= Locking fluid (Loctite).  
●
38– English  
SERVICE DATA  
3
5
7
5
20  
12  
17  
10  
▲
12  
8
▲
5
6
3
●
4
40  
4
9
4
English – 39  
TROUBLE SHOOTING  
Trouble shooting schematic  
Faults that can develop on the chain saw are  
divided into four groups as follows. In each cat-  
egory, possible malfunctions are shown on the left,  
with a list of possible faults on the right. The most  
probable fault is given first and so on.  
Idling (low rpm) (cont.)  
Starting  
Idles when L-screw  
closed  
Difficult starting  
Adjust L-screw  
Worn needle valve/needle  
Leaking control diaphragm/  
cover plate  
Control system sticking  
Worn throttle lever  
Faulty diffuser jet  
Air filter blocked  
Choke not working correctly  
Worn choke shaft  
Worn choke plate  
Fuel filter blocked  
Fuel line blocked  
Piston ring seized  
Blocked impulse channel  
Idling uneven  
Fuel filter blocked  
Fuel line blocked  
Leaking manifold  
Carburettor  
leaking fuel  
Loose carburettor mounting  
Worn throttle valve shaft  
Loose throttle valve screw  
Worn throttle valve  
Control system sticking  
Leak in throttle system (air or  
fuel)  
Loose or faulty fuel pipe  
Hole in diaphragm  
Worn needle valve/needle  
Control system sticking  
Control system set too high  
Leak in control system (air or  
fuel)  
Control diaphragm centre knob  
is worn  
Loose cover on carburettor  
pump side  
Hole in diaphragm  
Leaking control diaphragm/  
cover plate  
Flooding when  
the engine is not  
Worn needle valve  
Control system set too high  
running  
Crankcase leaking  
Control system sticking  
L-screw requires  
Fuel line blocked  
constant adjustment  
Control system set too high  
Control system sticking  
Control system (air or fuel)  
Leaking control diaphragm/  
cover plate  
Idling (low rpm)  
Will not idle  
Adjust L-screw  
Leaking manifold (intermediate)  
Loose carburettor mounting  
Loose or faulty fuel pipe  
Fuel filter blocked  
Faulty diffuser jet  
Crankcase leaking  
Fuel line blocked  
Control system set too high  
Control system sticking  
Control system damaged  
Worn needle valve  
Leaking control diaphragm/  
cover plate  
Fuel tank breather blocked  
Throttle shaft and lever stiff  
Throttle cable sticking  
Defective throttle return spring  
Bent throttle lever shaft stop  
Faulty diffuser jet  
Too much fuel at idling  
Control system incorrectly  
assembled  
Idling too rich  
Adjust L-screw  
Worn needle valve/needle  
Control system set too high  
Worn throttle lever  
Leaking control diaphragm/  
cover plate  
Control system sticking  
40– English  
TROUBLE SHOOTING  
Acceleration and retardation  
High rpm  
Adjust H-screw  
Blocked air filter  
Will not run at full  
throttle  
Does not accelerate  
Adjust L-screw  
Adjust H-screw  
Blocked fuel tankbreather  
Blocked fuel filter  
Fuel line blocked  
Blocked air filter  
Blocked fuel tankbreather  
Blocked fuel filter  
Loose or damaged fuel line  
Impulse channel leaking  
Impulse channel blocked  
Loose cover on carburettor  
pump side  
Fuel line blocked  
Loose or damaged fuel line  
Impulse channel blocked  
Loose cover on carburettor  
pump side  
Faulty pump diaphragm  
Leaking manifold  
Faulty pump diaphragm  
Leaking manifold  
Loose carburettor mounting  
Control system set too low  
Control system damaged  
Control system incorrectly  
assembled  
Leaking control diaphragm/cover  
Control system sticking  
Blocked silencer  
Loose carburettor mounting  
Throttle set too low  
Control system incorrectly  
assembled  
Control system sticking  
Faulty diffuser jet  
Blocked silencer  
Motor stalls when  
throttle released  
Adjust L-screw  
Adjust H-screw  
Faulty pump diaphragm  
Control system set too high  
Control system sticking  
Faulty diffuser jet  
Adjust H-screw  
Blocked fuel tankbreather  
Blocked fuel filter  
Impulse channel leaking  
Impulse channel blocked  
Loose cover on carburettor  
pump side  
Faulty pump diaphragm  
Blocked air filter  
Low power  
Over rich accelera-  
tion  
Adjust L-screw  
Adjust H-screw  
Blocked air filter  
Faulty pump diaphragm  
Faulty diffuser jet  
Control system sticking  
Leak in throttle system (air or  
fuel)  
Control system incorrectly  
assembled  
Loose diaphragm  
Hole in diaphragm  
Trouble shooting methods  
Leaking control diaphragm/cover  
Blocked fuel tank breather  
Blocked fuel filter  
In addition to faults given in the above schematic,  
trouble shooting can be carried out on a specific  
component or sub-system of the chain saw. The  
different testing procedures are described in  
respective sections and are as follows:  
Fuel line blocked  
Will not  
”four-stroke”  
Loose or damaged fuel line  
Impulse channel leaking  
Impulse channel blocked  
Loose cover on carburettor  
pump side  
1. Pressure testing the carburettor.  
See page 100.  
Faulty pump diaphragm  
Leaking manifold  
Loose carburettor mounting  
bolts  
Control system set too low  
Leak in throttle system (air or  
fuel)  
Control system incorrectly  
assembled  
2. Pressure testing the crankcase and cylinder.  
See page 114.  
3. Pressure testing the decompression valve.  
See page 114.  
4. Checking the operation of the chain brake.  
See page 47.  
Loose diaphragm  
Hole in diaphragm  
Leaking control diaphragm/cover  
English – 41  
SAFETY EQUIPMENT  
Chain brake  
A
Dismantling  
Dismantle the clutch cover and clean. See  
the operating instructions.  
Slide the hand guard forwards so that the  
brake is actuated.  
Loosen the screw on the hand guard and  
screw back 2 turns.  
Gentlyhitthescrewsothatthethreadedpart  
of the bushing can be removed.  
Dismantle the other part of the bushing by  
means of a punch.  
Remove the cylindrical pin A.  
All saws except 3120  
3120  
WARNING!  
Removethecoveronthechainbrakespring.  
The cover has 4 or 5 screws.  
If the clutch cover slides out of  
the vice's grip the spring can fly  
out with immense force resulting  
in personal injury!  
!
Wear protective glasses!  
Place the clutch cover in a vice with the jaws  
positioned as shown below and release the  
tubular pin B.  
Carefully knock out the tubular pin B.  
B
WARNING!  
If the brake is not 'on', the spring  
!
can fly out resulting in personal  
injury.  
Wear protective glasses!  
3120 continues on next page.  
Continues on next page.  
42– English  
SAFETY EQUIPMENT  
3120  
All saws except 3120  
Slide up the back edge of the  
spring with a screwdriver.  
Carefully unscrew the vice so that the pres-  
sure rod and the ratchet move out of the  
clutch cover.  
Dismantle the pressure rod from the brake  
band.  
Use a punch to knock out the pin holding the  
knee link.  
Removethescrewthatholdsthefixedendof  
the band.  
36, 41, 61, 268,  
272, 281 and 288  
40, 42, 45, 51,  
242,246,55,254,  
257,262and394  
Knock out the band's fixed end using a  
punch through the hole in the clutch cover  
and remove the loose parts.  
Lift up the band's fixed end using a screw-  
driver and remove the loose parts.  
English – 43  
SAFETY EQUIPMENT  
Cleaning and Inspection  
Clean and inspect all parts.  
The thickness of the brake band must not be  
under 0.8 mm at any point.  
Min. 0.8 mm  
Assembly  
Fit the band's fixed end into position on the  
clutch cover.  
All saws except 3120  
3120  
Fit the screw that holds the band's fixed end.  
Greasethekneelinkandknockinthetubular  
pin that holds the knee link.  
3120 continues on next page.  
Continues on next page.  
44– English  
SAFETY EQUIPMENT  
All saws except 3120  
3120  
Fit the spring and screw onto the pressure  
rod on the brake band.  
Note! Plastic sleeve.  
Slide the spring over the knee link's stud and  
pressdowntheoppositeendofthespringinto  
its recess.  
Bottom the screw onto the pressure rod  
thread and back off 4-5 turns.  
WARNING!  
If the clutch cover slides out of  
Fit the cover over the spring.  
!
the vice's grip the spring can fly  
out with immense force resulting  
in personal injury!  
Grease and fit the ratchet. Set the unit in a  
vice, positioned in the jaws as shown below.  
Continues on next page.  
3120 continues on next page.  
English – 45  
SAFETY EQUIPMENT  
3120  
All saws except 3120  
Carefullytightentheviceuntiltheholeforthe  
tubular pin and the ratchet align.  
Fit the hand guard, the two bushings and the  
screw.  
Carefully knock in the pin.  
Fit the cylindrical pin.  
Pull back the hand guard so that the brake is  
not actuated.  
Check the chain brake as described on the  
next page.  
46– English  
SAFETY EQUIPMENT  
Checking brake operation  
WARNING!  
After repair, the chain brake  
must be checked as set out in  
the following instructions.  
!
The engine should not be running  
during the test.  
Test that the chain brake comes on as  
follows:  
Hold the chain saw above a firm surface.  
The distance between the bar and the  
surface are shown in the table below.  
L
Bar length, L  
15-20 inches  
Height, H  
50 cm  
70 cm  
80 cm  
21-28 inches  
29-32 inches  
H
Release the front handle and let the chain  
saw rotate around the rear handle.  
When the bar nose hits the surface the  
chain brake should trip.  
English – 47  
SAFETY EQUIPMENT  
Chain catcher  
Description  
The chain catcher is intented to catch the  
chain if it should break.  
The chain catcher has a different design and  
is secured differently on the chain saws  
described in this manual.  
The following designs are used:  
• Aluminium angle.  
• Plastic angle.  
• Fixed roller.  
• Rotating roller.  
The following securing methods are used:  
• Using screws on the crankcase.  
• Using screws on the spike.  
• Using nuts on the spike.  
Replacing  
Dismantle the chain and bar. See the oper-  
ating instructions  
Check the chain catcher and replace if bro-  
ken or badly damaged.  
The tightening torque is stated in the service  
data  
Reassemble the chain and bar. See the  
operating instructions  
48– English  
SAFETY EQUIPMENT  
Muffler  
Dismantling  
B
WARNING!  
Do not touch the muffler until it  
has cooled. Risk of burns!  
!
C
A
If the saw is equipped with muffler mounting  
(A), unscrew this from the crankcase and  
muffler.  
Unscrew the muffler from the cylinder  
(M5 or M6 bolts, M5 or M6 nuts).  
Removethemuffler,gasketandcoolingplate  
(B) if the saw is so equipped.  
If the saw is equipped with a spark arrester  
(C), remove this.  
Saw 242 Cat  
Saws 36 and 41  
Dismantle the muffler  
as shown in the figure  
to the right.  
1
WARNING!  
A
The coating on and in the catalytic  
converter element (A) is hazardous  
to your health if touched. Wear  
protective gloves when working on  
a catalytic converter  
!
Dismantle the muffler as shown  
in the figure to the right.  
English – 49  
SAFETY EQUIPMENT  
Cleaning and Inspection  
WARNING!  
Clean all parts and check the following:  
• That the muffler and muffler mountings are  
not cracked or otherwise damaged.  
• That the gaskets are OK.  
The coating on and in the catalytic  
converter element (A) is hazardous  
to your health if touched. Wear  
protective gloves when working on  
a catalytic converter  
!
Assembly  
Assemble the muffler and fit to the  
cylinder. Tightening torque, see page  
20.  
Clean all contact surfaces.  
Saws 36 and 41  
Other saws  
If the saw is equipped with a spark arrester  
(C), fit this.  
WARNING!  
The coating on and in the cata-  
lytic converter element (A) is  
!
hazardous to your health if  
touched. Wear protective gloves  
when working on a catalytic  
converter  
Fit the cooling plate (B) if  
fitted, gasket and muffler on  
the cylinder.  
242 Cat  
Only specially treated bolts may be used on  
the catalytic converter (high temperature).  
See spare parts catalogue.  
1
Other saws  
See "Service data" regarding tightening torques.  
1. Secure the muffler on the cylinder using the two  
bolts (D).  
Tighten all bolts using the tightening  
torque set out in the "Service data".  
2. Assemble the muffler components using the four  
bolts (E).  
3. Secure the muffler to the crankcase using the two  
bolts (F) and Loctite.  
B
D
E
C
A
F
50– English  
SAFETY EQUIPMENT  
Stop switch  
A
Dismantling  
Remove the earth screw (A) and cable (B).  
Press the switch's securing tabs (C) towards  
each other and push out the switch.  
B
C
Cleaning and Inspection  
Clean the switch and check its resistance as  
follows:  
Connect an ohm meter as shown in the fig.  
The resistance should be:  
In the stop position  
In the run position  
less than 0.1 ohm.  
morethan1000ohm.  
Assembly  
Press the switch into the socket on the tank unit.  
Fit the earth screw (A) and cable (B).  
Note!Onsomemodelstheearthcableshould  
be connected to the earth screw.  
English – 51  
SAFETY EQUIPMENT  
Throttle lock  
Dismantling  
WARNING!  
The fuel used in the chain saw  
poses the following hazards:  
1. The liquid and its vapours  
are poisonous.  
2. Can cause skin irritation.  
3. Is highly inflammable.  
Saws40,45.  
Other saws.  
!
Seecontinuationonnextpage.  
Remove the tank unit from the engine  
assembly. See page 103.  
Dismantle the throttle lock pin (A)  
using a punch.  
Saw 3120.  
See continuation on next  
page.  
Saws61,268,268K,  
272XP, 272K, 272S,  
281XP, 288XP and  
394.  
A
Saws 36, 41, 42, 55,  
242XP, 246, 51,  
254XP, 257 and  
262XP.  
Saw 394  
Saws61,268,272XP,272K,  
272S, 281XP and 288XP.  
Turn the throttle lock as  
shown in the figure, and lift  
it out with the spring from  
the cut-out in the handle.  
Slide the throttle lock and  
remove it forwards as  
shown in the figure.  
Carefully prise up the lock  
from the slot and remove.  
Continues on next page.  
52– English  
SAFETY EQUIPMENT  
Saws36,41,42,55,242XP,246,51, 254XP,  
257 and 262XP.  
Saws61,268,268K,272XP,272K,272S,  
281XP, 288XP and 394.  
Remove the rubber element (A). Slide out  
the throttle pin (B) and lift out the throttle arm  
and spring.  
Dismantle the throttle pin (B) by using a  
punch.  
B
A
B
A
Saw 3120  
Dismantle the throttle. On saw 394, also  
remove the throttle cable.  
Remove the three pins with a punch.  
Saws 40 and 45  
Remove the three screws in the side of the  
handle as well as the screw holding the  
spring under the handle.  
Press the throttle lock down and move  
it and the trigger forwards until the  
back edge of the lock appears.  
Lift out the throttle lock and the throttle.  
Lift out the trigger lock.  
Lift out the throttle with cable from  
the front.  
Remove the springs where appropriate.  
English – 53  
SAFETY EQUIPMENT  
Cleaning and inspection  
Clean all parts.  
Check that the lock's activation  
mechanism is not worn. For examples of  
the activation mechanism, see the figure.  
Check that the springs, where fitted, are  
OK and have the correct tension.  
On those saws fitted with a throttle cable, check  
that the cable and lever are OK and run freely.  
54– English  
SAFETY EQUIPMENT  
Assembly  
Saws36, 40, 41, 45, 42,  
242XP, 246, 51, 55,  
254XP, 257 and 262XP.  
WARNING!  
Other saws.  
The fuel used in the chain saw  
poses the following hazards:  
1. The liquid and its vapours  
are poisonous.  
!
2. Can cause skin irritation.  
3. Is highly inflammable.  
Fit springs in appropriate cases.  
Saws 61,268,268K,  
Saw 3120.  
Saws36,41,42,242XP,  
246,51,55,254XP,257,  
262XP and 394.  
Saws 40, 45.  
272XP, 272K, 272S,  
281XP and 288XP.  
See next page.  
On saw 394, fit the cable  
to the trigger. Insert them  
into the handle from the  
front.  
Fit the cable to the trigger  
and install the throttle lock  
and trigger.  
Fit the trigger with the cable  
from the front.  
Fit the pin (B) and spring  
(when used).  
Fit the side of the handle  
using three screws on the  
side and one underneath,  
which holds the spring.  
Fit the spring and slide the  
throttle lock forwards from  
above so that its rear edge  
canbeslidinundertheedge  
of the handle.  
B
All saws except 40 and 45 continue on the next page.  
English – 55  
SAFETY EQUIPMENT  
Saws61,268,268K,  
272XP,272K,272S,  
281XP and 288XP.  
Saws36,41,42,242XP,  
246,51,55,254XP,257,  
262XP and 394.  
Saw 3120.  
Fit the throttle lock and  
spring. On saw 394, twist  
as shown in the figure  
when fitting.  
Fit the throttle arm and  
spring. Fit the pin and the  
two rubber dampers.  
Fit the three pins that hold  
the cable bracket, throttle  
lock and trigger.  
Fit the throttle lock from the  
front.  
Fit the throttle lock pin.  
Fit the tank unit. See page 105.  
56– English  
STARTER  
Dismantling  
Dismantle the starter  
See the operating instructions.  
Pull out the cord 20-30 cm andinsert it into  
the cut-out in the starter pulley rim.  
Some saws have several long cut-outs.  
Rotate the starter pulley anticlockwise until  
thespring-tensiononthestarterpulleyceases.  
Dismantlethestarterpulley'scentreboltand  
washer.  
WARNING!  
If the spring tension is released  
when lifting the starter pulley, the  
!
spring can fly out and cause per-  
sonal injury!  
Wear protective glasses!  
Lift out the starter pulley carefully.  
If the starter has a cord guide (A), remove  
this  
If the cord is to be replaced, cut it off and pull  
outthebitsfromthehandleandstarterpulley  
using a pair of long nosed pliers.  
WARNING!  
A
Ensure that the spring does not  
!
flyoutandcausepersonalinjury!  
Wear protective glasses!  
Ifthespringistobereplaced, removetheold  
spring from the starter pulley. Some saws  
have a protective plate over the spring.  
English – 57  
STARTER  
Cleaning and Inspection  
Clean all parts and check the following:  
WARNING!  
The starter cord.  
Ensure that the spring does not  
!
flyoutandcausepersonalinjury!  
The dogs in the starter pulley.  
That the pawls on the flywheel are OK, and  
springbacktowardsthecentreandmovefreely.  
Changing the ferrule  
Remove the parts of the old ferrule.  
Fit the new ferrule in the starter housing.  
B
A
Use a wrench, spacer (A) and ball (B).  
Splay out the ferrule on the inside as  
shown in the figure.  
58– English  
STARTER  
Assembly  
WARNING!  
Ensure that the spring does not  
flyoutandcausepersonalinjury!  
!
If a new spring is to be fitted, position in its  
security/holder so that the eye is over the  
stud in the starter cover.  
Slide in the spring and remove the security/  
holder.  
If a new cord is to be fitted, put the free end in the hole on the starter pulley. Grip the end using long  
nosed pliers and pull the cord through.  
42, 242, 246, 51, 55, 254,  
257,262, 394 and 3120.  
36 and 41.  
61, 268, 272, 281 and 288.  
Screwthecordtothestarter  
pulley.  
Knot the cord on the starter  
pulley.  
Secure the cord on the  
starter pulley.  
Continues on next page.  
English – 59  
STARTER  
Grease the return spring and starter pulley  
bearing.  
If the starter unit has a cover plate (B) over  
the spring, fit the plate.  
B
Fit the starter pulley. Rotate back and forth  
until the starter pulley catches in the spring.  
Fit the starter pulley washer and bolt and  
tighten the bolt to 4 Nm.  
If the starter has a cord guide (A), fit this.  
Pulloutthecordthroughtheholeinthecover  
and fit the handle, secure with a double knot.  
A
Pull out the cord 20-30 cm and insert it into  
the cut-out on the starter pulley rim. Some  
saws have several long cut-outs.  
Rotate the starter pulley clockwise until the  
cord is correctly tensioned.  
Check the cord tension  
A. Pull out the cord completely and hold the  
pulley with your thumb.  
B. Inthispositionitshouldbepossibletoturn  
the starter pulley a further 1/2 - 3/4 turn.  
Fit the starter on the crankcase. Tighten the  
bolts to 4 Nm.  
60– English  
ELECTRICAL SYSTEM  
Ignition system  
In the event of a fault in the ignition system  
the ignition module should be checked before  
dismantling the ignition system.  
Check the ignition module as follows:  
• Connect test spark plug 502 71 13-01 to the  
HT lead and clamp the test spark plug to the  
cylinder.  
• Turn the engine over using the starter.  
• If the test spark plug sparks the ignition  
module is OK.  
Dismantling  
Remove the cylinder cover and the starter unit.  
Remove the spark plug and fit the piston stop.  
Saws 36 and 41.  
Loosen the cable that runs to the stop  
switch from the ignition module.  
Release the cables from the guide rail and  
remove the guide rail.  
• Loosen the flywheel nut and unscrew it 1  
turn  
• Tap the nut quickly with a hammer so that  
the flywheel comes loose  
• Remove the nut and flywheel.  
Other saws, see next page.  
English – 61  
ELECTRICAL SYSTEM  
All saws except 36 and 41.  
Unscrew the two pawls and springs  
located on the flywheel.  
Fit puller 502 51 49-02 and loosen the  
flywheel.  
Remove the puller, nut and flywheel.  
Loosen the flywheel nut and undo until it  
aligns with the end of the shaft.  
Continuation all saws  
The generator can be unscrewed if the saw is  
fitted with a handle heating system.  
Remove the ignition coil.  
Remove all parts so that the cable can be  
released. See applicable sections.  
62– English  
ELECTRICAL SYSTEM  
Cleaning and Inspection  
Clean all parts, especially the flywheel and  
shaft taper.  
Check that the flywheel is not cracked or  
damaged in any other way.  
Assembly  
Fit the generator if the saw is fitted with  
handle heating.  
Tighten the bolts to 4 Nm and lock using  
Loctite.  
Fit the cable to the actual contact on the  
saw. Adjust the length of the cable by  
knotting it.  
Place the flywheel on the crankshaft. Rotate  
gently until the flywheel's key mates in the  
keyway on the shaft  
• Replace the flywheel washer and nut.  
Tightening torque, see "Service data".  
• Remove the piston stop.  
• Fit the ignition module  
without tightening the  
screws.  
• Turn the flywheel so that its  
magnet is beside the  
ignition module.  
Continue  
assembly on  
next page.  
English – 63  
ELECTRICAL SYSTEM  
• Insert feeler gauge 502 51 34-02  
(0.3 mm) between the ignition module  
and the flywheel's magnet.  
• Push the ignition module towards the  
flywheel and tighten the bolts to 4 Nm.  
Fit the guide rail, insert the cables and fit  
the cable to the ignition module.  
Other saws.  
Saws 42, 242, 246, 281 and 288.  
Fit the starter and cylinder cover.  
Fit the ignition coil, which is located next to  
the carburettor and connect the cables.  
Fit the starter and cylinder cover.  
Fitting the spark plug cover  
Make a hole in the HT cable using pliers  
502 50 06-01.  
Push the HT cable through the spark plug  
cover and fit the contact spring using the  
pliers.  
Slide the spark plug cover over the contact  
spring.  
Stop switch  
The stop switch is described in the section  
"Safety equipment". See page 51.  
64– English  
ELECTRICAL SYSTEM  
Handle heating  
Description  
Some saws are equipped with an electric  
handleheating.Thisconsistsofthefollowing  
parts:  
• Generator.  
• Power switch.  
• Heater loop in the tank unit.  
• Handle loop with heater loop.  
(One or two loops).  
B
The above components are connected in  
series, which means that if there is a fault in  
one, all components stop working.  
The wiring diagram is shown in the figure to  
the right. The order of components can vary  
from saw to saw.  
E
Trouble shooting  
A1  
Trouble shooting can take place with most  
components connected to the saw. An  
ohm meter is required for trouble shooting.  
A2  
C
D
Measurement points:  
A1 and A2 Earth. E.g. the cylinder  
A1 - B  
B - C  
C - D  
Measurement of the generator  
Measurement of the handle loop  
Measurementoftheheaterloops  
in the rear handle  
Before trouble shooting individual  
components remove the power switch and  
disconnect one of the switch's cables.  
Remove other components as necessary.  
E.g. the cylinder cover. See the operating  
instructions.  
D - A2  
Measurementofthepowerswitch  
Troubleshootingindividualcomponents,see  
next page.  
English – 65  
ELECTRICAL SYSTEM  
Checking the generator  
Check the handle loop  
Connect the ohm meter to the cylinder  
(point A1) and point B. The ohm meter  
should read 0.9-1.3 ohm.  
Replace a generator that has higher or  
lower values.  
Connect the ohm meter to points B and C.  
The ohm meter should read 3-4 ohm.  
Replace the handle loop that has a higher  
value.  
B
B
C
A1  
Checking the heat loops in the rear handles  
Checking the power switch  
Connect the ohm meter to points C and D.  
The ohm meter should read 0.7-2.5 ohm.  
Replace a heat loops that has higher  
values.  
Connect the ohm meter across the switch.  
The ohm meter should read more than  
1000 ohm with the switch in position "0".  
The ohm meter should read, at the highest,  
0.1 ohm with the switch in position "1".  
D
C
66– English  
CENTRIFUGAL CLUTCH  
Dismantling  
Remove the bar and chain. See the operat-  
ing instructions.  
On 268K and 272K, remove the cutting  
attachment. See the operating instructions.  
On 272S, remove the grinder attachment.  
See the operating instructions.  
Remove the spark plug and insert the piston  
stop.  
Use a spanner and remove the clutch. On  
saws 36 and 41 use the service tool no. 530  
03 11-12.  
Note! Left-hand thread.  
Saws with three  
coil springs.  
Saws with one  
long spring.  
Saws with three C-springs.  
Prise out the spring heels  
usingascrewdriver. Remove  
the springs from the other  
side using circlip pliers. Then  
remove the clutch shoes.  
Remove the springs using a  
screwdriver.  
Then remove the clutch  
shoes.  
Remove the spring by first  
lifting a shoe using a suitable  
spacer (A).  
Then remove the clutch  
shoes.  
A
Remove the clutch drum and needle bearing.  
English – 67  
CENTRIFUGAL CLUTCH  
Cleaning and Inspection  
Clean all parts and inspect the following:  
Clutch  
withoutchamfers.  
shoes  
Clutch shoes  
with chamfers.  
That measurement A is not below 1 mm.  
A
That measurement B is not under 1 mm.  
B
Check that there is no play between the  
clutch shoe and clutch hub  
Check for wear on the chain sprocket.  
Check the condition of the needle bearing  
and the bearing surface on the crankshaft.  
That the clutch drum friction surface and  
bearing surface are undamaged.  
68– English  
CENTRIFUGAL CLUTCH  
Assembly  
Grease the needle bearing (C) and fit onto  
the crankshaft. Then fit the clutch drum.  
NOTE! The bearing can also be greased  
later through the hole on the crankshaft.  
C
Topreventimbalanceallclutchshoesshould  
be replaced at the same time.  
NOTE! The clutch  
springs should not be  
opened out more than  
necessary. Risk of  
deformation.  
Saws with three  
coil springs.  
Saws with one  
long spring.  
Saws with three C-springs.  
Locate the clutch shoes on  
the hub and fit the springs  
with the help of pliers.  
Locatetheclutchshoesonthe  
hub. Lift a shoe using a suit-  
able spacer (A) and fit the  
Locatetheclutchshoesonthe  
hub and fit the springs with the  
help of circlip pliers.  
spring.  
A
Using a spanner secure the clutch centre.  
On saws 36 and 41 use service tool no.  
530 03 11-12.  
Note! Left-hand thread.  
Fit the chain and bar. See the operating instruc-  
tions. On 268K and 272K, fit the cutting attach-  
ment.  
Remove the piston stop and fit the spark  
plug.  
See the operating instructions.  
English – 69  
LUBRICATION SYSTEM  
Dismantling  
Dismantle the following parts:  
• Starter. See the operating instructions  
• Centrifugal clutch. See page 67.  
Saw 3120. See page 72  
Other saws.  
Saws 36, 40, 41, 45, 51 and 55. See page 72  
Remove the pump drive and washer.  
Undo the three bolts (A) and remove the  
oil pump. Some pumps have to be  
removed by using extractor screws. M5  
screws should be inserted into the 2  
threaded holes in the pump body and  
tightened equally to lift the pump and  
thrust washer. Other pumps have a cut-out  
(C) for a screwdriver to prise off the pump.  
Both types are shown below.  
Saws 61, 268, 272XP. See next page.  
Saws 281XP and 288 XP. See next page.  
Saw 394. See page 72.  
Saws 42, 242XP, 246, 254XP, 262XP and 257.  
A
B
C
Dismantle the oil pump as follows:  
1. Unscrew screw (A) and remove locking  
clip (B).  
D
E
2. Undo screw (C).  
3. Lever out the pump piston (D) and  
plastic plug (E) using a screwdriver.  
B
A
4. Remove the seal (F).  
C
F
70– English  
LUBRICATION SYSTEM  
Saws 61, 268, 272XP.  
E
C
D
Dismantle the oil pump as follows:  
F
1. Remove the lock washer (A), washer,  
spring and adjuster screw (B).  
2. Remove the locking lacquer and undo  
screw (C).  
B
G
3. Knock the edge of the pump housing  
against a piece of wood so that the  
pump piston (D) slides out of the  
housing.  
4. Remove the pinion (E) with washers  
and springs.  
5. Remove the pin (F).  
6. Remove the seal (G).  
7. If necessary remove the O-ring (H).  
A
H
Saws 281XP and 288 XP.  
Dismantle the oil pump as follows:  
C
B
F
1. Undo the adjuster screw (A).  
2. Remove the plug (B) with pump piston  
(C) and spring with washers.  
A
3. Dismantle the O-ring (D). Replace if  
necessary.  
4. If necessary, replace the seal (E).  
5. If necessary, replace the O-ring (F).  
D
E
English – 71  
LUBRICATION SYSTEM  
Saw 394.  
C
B
D
Dismantle the oil pump as follows:  
1. Dismantle the screw (A) so that the  
spring and latch pin (B) can be  
removed.  
2. Lever out the pump piston (C) with the  
plastic plug (D) using a screwdriver.  
3. Remove the seal (E).  
E
A
Dismantle the oil pump as follows:  
Saw 3120.  
1. Undo the screws (A) and remove the parts as  
shown in the figure below.  
2. Undo screw (B). NOTE! Left-hand thread.  
Undo the three bolts that hold  
the oil pump and lift up the pump  
by the cut-out for the adjuster  
screw. Lift off the pump and  
loosen the wire for manual oil  
supply.  
B
A
72– English  
LUBRICATION SYSTEM  
Saws 36, 40, 41, 45, 51 and 55.  
Dismantle the chain guide plates as shown  
in respective diagrams below.  
36/41  
40/45  
51/55  
Saws 51 and 55.  
Saws 36, 40, 41 and 45.  
Undo the two bolts and lift off the pump  
and the upper seal.  
Lift off the pump and the upper seal.  
Take the pump apart as shown in the exploded view on  
the next page.  
English – 73  
LUBRICATION SYSTEM  
D
E
F
G
E
F
G
B C  
A
C
B
A
40/45  
36/41  
A. Lower seal.  
B. Pump cylinder.  
C. Upper seal.  
D. Chain guide plate.  
E. Pump housing.  
F. Pump piston.  
G. Worm gear.  
D
E
F
G
C
B
A
50/51  
74– English  
LUBRICATION SYSTEM  
Dismantling the oil pump's  
worm gear  
On some saws the worm gear for the oil  
pump is pressed on the crankshaft.  
Remove the worm gear by using the  
service tool for the saw in question. See  
"Tools".  
First screw the tool onto the entire worm  
gear  
Turn the screw until the worm gear is  
removed.  
English – 75  
LUBRICATION SYSTEM  
Cleaning and Inspection  
Clean all parts and check the following  
when appropriate to the saw in question.  
That the taper on the adjuster screw  
shows no signs of wear.  
That the pump piston's eccentric face does  
not show signs of wear.  
That the pump piston's pinion gear is undamaged.  
That the worm gear on the oil pump drive  
is undamaged.  
That all seals are undamaged.  
The oil pipe is not blocked and the filter  
screen is clean.  
76– English  
LUBRICATION SYSTEM  
Assembling the worm gear  
Screw the worm gear into the dismantling  
tool and press the worm gear onto the  
crankshaft until it bottoms against the  
collar.  
On those saws where the oil pump worm  
gear is pressed on the crankshaft.  
Assembling the oil pump  
Saws 42, 242XP, 246, 254XP, 262XP and 257.  
Fit the oil pump as follows:  
1. Apply SAE 30 oil to all moving parts.  
2. Insert the pump piston (D) with  
washers and spring.  
D
E
3. Press in the pump piston a little more  
and screw in the adjuster screw (C).  
4. Insert the plastic plug (E).  
5. Refit screw (A) and locking clip (B).  
6. Fit the seal (F).  
B
A
C
F
See continuation, page 80.  
Saws 61, 268, 272XP.  
E
C
D
Fit the oil pump as follows:  
F
1. Apply SAE 30 oil to all moving parts.  
2. Fit the seal (G) if necessary.  
3. Press in pin (F).  
4. Locate the pinion (E) with washers and  
spring.  
B
G
I
5. Insert the pump piston (D) through the  
pinion, spring and washers in the pump  
housing.  
6. Fit screw (C). The screw should be  
locked using Loctite or locking lacquer.  
7. Fit the adjuster screw (I) with washers,  
spring and locking clip (A).  
A
H
8. Fit the O-ring (H).  
See continuation, page 80.  
English – 77  
LUBRICATION SYSTEM  
Saws 281XP and 288 XP.  
Fit the oil pump as follows:  
C
B
1. Apply SAE 30 oil to all moving parts  
2. Fit the seal (E) if necessary.  
3. Fit the plug (B) and spring with washers  
on the pump piston (C) and fit the unit  
in the pump housing.  
F
A
4. Fit the adjuster screw (A) in the pump  
housing, and through the hole in plug  
(B).  
D
E
5. Fit the O-rings (D) and (F).  
Saw 394.  
See continuation, page 80.  
Fit the oil pump as follows:  
C
D
1. Apply SAE 30 oil to all moving parts.  
2. Fit the pump piston (C) with washers  
and spring in the pump housing.  
3. Fit the latch pin (B), press in the pump  
piston (C) a little more and fit the  
adjuster screw (A).  
B
4. Fit the seal (E).  
5. Fit the plug (D).  
E
A
See continuation, page 80.  
78– English  
LUBRICATION SYSTEM  
Saw 3120.  
Fit the oil pump as follows:  
1. Apply SAE 30 oil to all moving parts  
2. Fit the seal (C).  
5. Fit lever arm (F).  
6. Fit units (B-F-G) with spring (H) and  
screw in position using screws (A) and  
latch (J).  
7. Remove the screwdriver.  
8. Fit a new O-rings (K) and (L).  
3. Fit the pump piston (D) with spring.  
Press in the piston and hold it in  
position with a screwdriver from the  
pump housing's inside in slot (E).  
4. Fit screw (B) so that it is positioned  
approx. one turn from the bottom.  
NOTE! Left-han
F
D
E
H
G
J
C
K
B
A
Fit the wire for manual oil supply.  
See continuation on next page.  
English – 79  
LUBRICATION SYSTEM  
Saws 42, 61, 242, 246, 254, 257, 262, 268, 272, 281, 288, 394 and 3120.  
Saws 61, 268, 272, 281 and 288  
Use the tapered sleeve which  
is placed on the shaft when  
fitting the oil pump. Otherwise  
the seals will be damaged.  
1. Lubricate the pinion gear with grease.  
2. Fit the oil pump on the saw by  
tightening the three bolts.  
3. If the tapered sleeve has been used,  
remove it.  
4. Fit the centrifugal clutch.  
See page 69.  
5. Fit the bar and chain.  
6. Adjust the oil pump for the correct oil flow.  
See the operating instructions.  
80– English  
LUBRICATION SYSTEM  
Saws 36, 40, 41, 45, 51 and 55.  
Fit the oil pump as follows:  
A. Lower seal.  
B. Pump cylinder.  
C. Upper seal.  
1. Apply SAE 30 oil to all moving parts.  
2. Fit the worm gear (G) on the  
crankshaft, if necessary  
D. Chain guide plate.  
E. Pump housing.  
F. Pump piston.  
G. Worm gear  
3. Fit the pump piston (F) in the pump  
cylinder (B).  
4. Fill the pump recess with grease.  
5. Fit the unit in the pump housing (E).  
Ensure the pump cylinder's cut-out  
aligns in the pump housing.  
6. Fit the lower seal (A) on the crankcase.  
D
E
F
G
E
F
G
B C  
A
C
B
A
40/45  
36/41  
D
E
F
G
C
B
A
50/51  
Saws 36, 40, 41 and 45, see  
continuation on the next page.  
Saws 51 and 55, see continuation  
on the next page.  
English – 81  
LUBRICATION SYSTEM  
Saws 36, 40, 41 and 45.  
Saws 51 and 55.  
Fit the oil pump in the crankcase and fit  
the upper seal.  
Fit the oil pump in the crankcase, tighten  
the two bolts and fit the upper seal.  
Fit the chain guide plates according to  
respective diagrams below.  
36/41  
40/45  
51/55  
Fit the bar and chain.  
82– English  
CARBURETTOR  
Description  
The diagrams in this description do not  
correspond with the carburettor fitted on  
the chain saws. They serve only to show  
the principles of design and operation.  
WARNING!  
Thefuelusedinthechainsawposes  
the following hazards:  
1. The liquid and its vapours are  
poisonous.  
!
2. Can cause skin irritation.  
3. Is highly inflammable.  
Design  
The carburettor consists of three sub-systems:  
• Metering unit, A.  
• Mixing venturi, B.  
• Pump unit, C.  
The metering unit (A) contains the jets and  
fuel control functions. It is here the correct  
amount of fuel for the given engine speed  
and power is metered.  
A
The mixing venturi (B) houses the choke,  
throttle valve and diffuser jets. Here air is  
mixed with the fuel to give a fuel/air  
mixture that can be ignited by the ignition  
spark.  
B
In the pump unit (C), fuel is pumped from the  
fuel tank to the metering unit. One side of the  
pump diaphragm is connected to the crankcase  
and pulses in time with the pressure changes in  
the crankcase. The other side of the diaphragm  
pumps the fuel.  
C
English – 83  
CARBURETTOR  
Operation  
The carburettor operates differently in the  
following modes:  
• Cold start  
• Idling  
• Part throttle  
• Full throttle  
In the cold start mode the choke valve (D)  
is fully closed. This increases the vacuum  
in the carburettor and fuel is easier to suck  
from all the diffuser jets (E, F and G). The  
throttle valve (H) is partly open.  
D
E
F
G
In the idling mode (H) the throttle valve is  
closed. Air is sucked in through an  
aperture in the throttle valve and a small  
amount of fuel is supplied through the  
diffuser jet (G).  
H
G
In the part throttle mode the throttle valve  
(H) is partially open. Fuel is supplied  
through the diffuser jets (F and G).  
H
F
G
In the full throttle mode both valves are  
open and fuel is supplied through all three  
diffuser jets (E, F and G).  
E
F
G
84– English  
CARBURETTOR  
Dismantling  
WARNING!  
The fuel used in the chain saw  
poses the following hazards:  
1. The liquid and its vapours are  
poisonous.  
2. Can cause skin irritation.  
3. Is highly inflammable.  
!
Dismantle all parts necessary and remove  
the carburettor from the saw. On some  
models the cylinder needs to be loosened  
and lifted to be able to remove the  
carburettor.  
See the carburettor in question on the next  
four pages and the instructions below.  
”Semi fixed jet”/”fixed jet”  
Some carburettors have an extra jet (semi  
fixed jet). The jet is of brass and is located  
in the metering unit and is used to give a  
fuel supplement. On average 10% of the  
fuel passes through the jet.  
Plugs  
When cleaning the carburettor the plugs  
must be removed. Remove as follows:  
Below or next to the jet is a screen which  
needs to be cleaned.  
1. Drill a hole in the plug.  
2. Insert a screwdriver or punch in the hole  
and prise up the plug.  
Dismantle the jet and/or screen in one of  
the following ways:  
1. Knock the unit into the venturi using a  
punch and take the unit apart. (some  
Tillotson models).  
2. Dismantle the lock washer over the jet  
and lift off the jet and screen.  
English – 85  
CARBURETTOR  
Tillotson HS 228 B  
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
E
F
G
2. Undo the screw (H) and take out  
the needle valve (C) with lever arm,  
shaft and spring.  
D
3. Remove the cover (E) over the pump unit  
and carefully remove the gasket (F) and  
the pump diaphragm (G).  
J
4. Using a needle or the like carefully remove  
the fuel screen (D).  
C
5. Unscrew the high and low speed jet  
screws.  
H
B
A
6. Remove the plugs (J).  
See page 85.  
7. If necessary remove the throttle and choke  
valves as well as the shafts, lever arms  
and springs.  
Tillotson HS 255 B  
1. Remove the cover (A) over the mete
unit and carefully remove the control  
diaphragm (B) with the gasket.  
D
2. Undo the screw (H) and take out  
the needle valve (C) with lever  
arm, shaft and spring.  
3. Remove the cover (E) over the pump
and carefully remove the gasket (F)
the pump diaphragm (G).  
4. Using a needle or the like carefully  
remove the fuel screen (D).  
5. Unscrew the high and low speed jet  
screws.  
6. Remove the plugs (J). See page 85.  
7. If necessary remove the throttle and  
choke valves as well as the shafts, le
arms and springs.  
8. Remove the speed governor (I). (Only  
272K, 268K and 272S).  
9. Remove the ”semi fixed jet” (K). See page 85.  
86– English  
CARBURETTOR  
Tillotson HS 260 A  
E
F
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
G
2. Undo the screw (H) and take out the  
needle valve (C) with lever arm, shaft and  
spring.  
D
3. Remove the cover (E) over the pump unit  
and carefully remove the gasket (F) and  
the pump diaphragm (G).  
J
H
4. Using a needle or the like carefully remove  
the fuel screen (D).  
C
5. Unscrew the high and low speed jet  
screws.  
H
K
B
A
6. Remove the plugs (J). See page 85.  
7. If necessary remove the throttle and choke  
valves as well as the shafts, lever arms  
and springs.  
8. Remove the ”semi fixed jet” (K). See page 85.  
A
B
Walbro HDA and HD  
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
2. Undo the screw (H) and take out the  
needle valve (C) with lever arm, shaft and  
spring.  
H
C
3. Remove the cover (E) over the pump  
unit and carefully remove the gasket (F)  
and the pump diaphragm (G).  
J
4. Using a needle or the like carefully remove  
the fuel screen (D).  
D
5. Unscrew the high and low speed jet  
screws.  
G
F
6. Remove the plug (J). See page 85.  
7. If necessary remove the throttle and choke  
valves as well as the shafts, lever arms and  
springs.  
E
English – 87  
CARBURETTOR  
Walbro WJ  
E
F
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
G
D
2. Undo the screw (H) and take out the  
needle valve (C) with lever arm, shaft and  
spring.  
3. Remove the cover (E) over the pump unit  
and carefully remove the gasket (F) and  
the pump diaphragm (G).  
J
4. Using a needle or the like carefully remove  
the fuel screen (D).  
C
K
H
5. Unscrew the high and low speed jet  
screws.  
6. Remove the plug (J). See page 85.  
B
A
7. If necessary remove the throttle and choke  
valves as well as the shafts, lever arms  
and springs.  
8. Remove the ”semi fixed jet” (K). See page 85.  
Walbro WG  
A
B
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
2. Undo the screw (H) and take out the  
needle valve (C) with lever arm, shaft and  
spring.  
H
C
K
J
3. Remove the cover (E) over the pump unit  
and carefully remove the gasket (F) and  
the pump diaphragm (G).  
4. Using a needle or the like carefully remove  
the fuel screen (D).  
5. Unscrew the low speed jet screws.  
6. Remove the plugs (J). See page 85.  
D
G
F
7. If necessary remove the throttle and choke  
valves as well as the shafts, lever arms  
and springs.  
8. Remove the ”semi fixed jet” (K). See page 85.  
E
88– English  
CARBURETTOR  
Walbro WT  
E
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
2. Undo the screw (H) and take out the  
needle valve (C) with lever arm, shaft  
and spring.  
F
D
G
3. Remove the cover (E) over the pump  
unit and carefully remove the gasket (F)  
and the pump diaphragm (G).  
C
4. Using a needle or the like carefully remove  
the fuel screen (D).  
J
5. Unscrew the high and low speed jet  
screws.  
6. Remove the plug (J). See page 85.  
B
A
H
K
7. If necessary remove the throttle and choke  
valves as well as the shafts, lever arms  
and springs.  
8. Remove the ”semi fixed jet” with diffuser  
jet (K). See page 85.  
ZAMA C1Q-EL1  
A
B
1. Remove the cover (A) over the metering  
unit and carefully remove the control  
diaphragm (B) with the gasket.  
H
2. Undo the screw (H) and take out the  
needle valve (C) with lever arm, shaft and  
spring.  
3. Remove the cover (E) over the pump unit  
and carefully remove the gasket (F) and  
the pump diaphragm (G).  
C
K
4. Using a needle or the like carefully remove  
the fuel screen (D).  
D
G
F
5. Unscrew the high and low speed jet  
screws.  
6. If necessary remove the throttle and  
choke valves as well as the shafts, lever  
arms and springs.  
E
English – 89  
CARBURETTOR  
Cleaning and Inspection  
WARNING!  
The fuel used in the chain saw  
!
poses the following hazards:  
1. The liquid and its vapours are  
poisonous.  
2. Can cause skin irritation.  
3. Is highly inflammable.  
Clean all components in petrol. Wear  
gloves or skin protection cream.  
WARNING!  
Neverdirectthecompressedair  
jet towards the body. Air can be  
forcedintothebloodstreamand  
can cause fatality.  
!
Use compressed air to dry the petrol on the  
components. Direct the air through all  
channels in the carburettor housing and  
ensure that they are not blocked.  
Refer to the carburettor diagram in  
question on the previous pages and check  
the following:  
1. That the gasket and pump and control  
diaphragms are undamaged.  
2. That there is no play on the throttle and  
choke valve shafts.  
3. That the needle valve and its lever are  
not worn.  
4. That the fuel screen is undamaged  
5. That the tips of the high and low speed  
jet screws are not damaged.  
6. On Tillotson HS 255 B, that the speed  
governor (I) is clean.  
7. That the air intake manifold is not cracked.  
90– English  
CARBURETTOR  
Assembly  
Refer to the carburettor in question on the  
next eight pages. A pressure test, see  
page 100, should be carried out after  
assembling and before the carburettor is  
refitted to the saw.  
WARNING!  
The fuel used in the chain saw  
poses the following hazards:  
1. The fluid and its vapours are  
poisonous.  
!
2. Can cause skin irritation.  
3. Is highly inflammable.  
”Semi fixed jet”/”fixed jet”  
Plugs  
When cleaning the carburettor the plugs  
must be removed.  
Reassemble as follows:  
Some carburettors have an extra jet (semi  
fixed jet). The jet is of brass and is located  
in the metering unit and is used to give a  
fuel supplement. On average 10% of the  
fuel passes through the jet.  
1. Place the plug in the hole with the  
convex side facing upwards.  
Below or next to the jet is a screen which  
needs to be cleaned.  
2. Expand the plug by using a punch on  
the top side.  
Reassemble the jet and/or screen in one  
of the following ways:  
1. Put together the unit and fit it in the  
carburettor by means of a punch (Some  
Tillotson models).  
2. Fit the jet with screen and lock washer.  
English – 91  
CARBURETTOR  
Tillotson HS 228 B  
E
F
Maintain a high level of cleanliness
reassembling the carburettor. Even
particles of dirt can cause operating  
problems.  
G
1. If the throttle and choke valves, sh
lever arms and springs have been  
dismantled these must be reassem
Lubricate the shaft bearings using
light oil.  
D
2. Fit the plugs (J). See page 91.  
J
3. Fit the high and low jet screws and  
springs. NOTE! Do not tighten the  
screws against the seats. This can  
damage the seats and needle tips.  
C
H
4. Fit the fuel screen (D) by using the  
handle of a small screwdriver.  
B
A
5. Fit the pump diaphragm (G), gaske
(F) and cover (E) on the pump unit.  
6. Fit the needle valve (C) with lever arm,  
shaft and spring and tighten screw (H).  
7. Check, using or a ruler or the like, that  
the lever arm is level with the chamber  
floor. See the figure to the lower right.  
The lever arm can be bent if necessary  
to achieve the correct settings.  
8. Fit the control diaphragm (B) with  
gasket and cover (A) on the metering  
unit.  
9. Carry out a pressure test.  
See page 100  
.
92– English  
CARBURETTOR  
Tillotson HS 255 B  
D
Maintain a high level of cleanliness w
reassembling the carburettor. Even sm
particles of dirt can cause operating pr
lems.  
1. If the throttle and choke valves, shaft
lever arms and springs have been  
dismantled these must be reassembl
Lubricate the shaft bearings using a l
oil.  
2. Fit the plugs (J). See page 91.  
3. Fit the ”semi fixed jet” (K). See page
4. Fit the high and low jet screws and sp
NOTE! Do not tighten the screws aga
the seats. This can damage the seats
needle tips.  
5. Fit the fuel screen (D) by using the ha
of a small screwdriver.  
6. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
7. Fit the needle valve (C) with lever arm,  
shaft and spring and tighten screw (H).  
8. Check, using or a ruler or the like, that the  
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve  
the correct settings.  
9. Fit the speed governor (I). Lock with  
Loctite or locking lacquer. (Only applies to  
272K, 268K and 272S).  
10. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
11. Carry out a pressure test.  
See page 100.  
English – 93  
CARBURETTOR  
Tillotson HS 260 A  
E
F
Maintain a high level of cleanliness w
reassembling the carburettor. Even s
particles of dirt can cause operating  
problems.  
G
1. If the throttle and choke valves, sha
lever arms and springs have been  
dismantled these must be reassem
Lubricate the shaft bearings using a
oil.  
D
2. Fit the plugs (J). See page 91.  
J
H
3. Fit the ”semi fixed jet” (K). See pag
C
4. Fit the high and low jet screws and  
springs. NOTE! Do not tighten the s
against the seats. This can damage
seats and needle tips.  
H
K
B
A
5. Fit the fuel screen (D) by using the
of a small screwdriver.  
6. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
7. Fit the needle valve (C) with lever arm,  
shaft and spring and tighten screw (H).  
8. Check, using or a ruler or the like, that the  
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve  
the correct settings.  
9. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
10. Carry out a pressure test. See page 100.  
94– English  
CARBURETTOR  
Walbro HDA och HD  
A
B
Maintain a high level of cleanliness when  
reassembling the carburettor. Even small  
particles of dirt can cause operating prob-  
lems.  
H
C
1. If the throttle and choke valves, shafts,  
lever arms and springs have been  
dismantled these must be reassembled.  
Lubricate the shaft bearings using a  
light oil.  
J
2. Fit the plugs (J). See page 91.  
3. Fit the high and low jet screws and springs.  
NOTE! Do not tighten the screws against  
the seats. This can damage the seats and  
needle tips.  
D
G
F
4. Fit the fuel screen (D) by using the handle  
of a small screwdriver.  
5. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
E
6. Fit the needle valve (C) with lever arm,  
shaft and spring and tighten screw (H).  
7. Check, using or a ruler or the like, that the  
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve  
the correct settings.  
8. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
9. Carry out a pressure test. See page 100  
.
English – 95  
CARBURETTOR  
Walbro WJ  
E
F
Maintain a high level of cleanliness when  
reassembling the carburettor. Even small  
particles of dirt can cause operating prob-  
lems.  
G
D
1. If the throttle and choke valves, shafts, lever  
arms and springs have been dismantled  
these must be reassembled. Lubricate the  
shaft bearings using a light oil.  
J
2. Fit the plugs (J). See page 91.  
C
K
H
3. Fit the ”semi fixed jet” (K). See page 91.  
4. Fit the high and low jet screws and springs.  
NOTE! Do not tighten the screws against  
the seats. This can damage the seats and  
needle tips.  
B
A
5. Fit the fuel screen (D) by using the handle  
of a small screwdriver.  
6. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
7. Fit the needle valve (C) with lever arm, shaft  
and spring and tighten screw (H).  
8. Check, using or a ruler or the like, that the  
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve the  
correct settings.  
9. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
10. Carry out a pressure test. See page 100.  
96– English  
CARBURETTOR  
Walbro WG  
A
B
Maintain a high level of cleanliness when  
reassembling the carburettor. Even small  
particles of dirt can cause operating prob-  
lems.  
H
C
1. If the throttle and choke valves, shafts,  
lever arms and springs have been  
K
J
dismantled these must be reassembled.  
Lubricate the shaft bearings using a light oil.  
2. Fit the plugs (J). See page 91.  
3. Fit the ”fixed jet” (K). See page 91.  
4. Fit the high and low jet screws and springs.  
NOTE! Do not tighten the screws against  
the seats. This can damage the seats and  
needle tips.  
D
G
F
5. Fit the fuel screen (D) by using the handle  
of a small screwdriver.  
6. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
E
7. Fit the needle valve (C) with lever arm, shaft  
and spring and tighten screw (H).  
8. Check, using or a ruler or the like, that the  
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve the  
correct settings.  
9. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
10. Carry out a pressure test. See page 100.  
English – 97  
CARBURETTOR  
Walbro WT  
E
Maintain a high level of cleanliness w
reassembling the carburettor. Even s
particles of dirt can cause operating  
problems.  
F
D
G
1. If the throttle and choke valves, shaf
lever arms and springs have been  
dismantled these must be reassemb
Lubricate the shaft bearings using a
C
2. Fit the plugs (J). See page 91.  
J
3. Fit the ”semi fixed jet” (K). See page
4. Fit the high and low jet screws and s
NOTE! Do not tighten the screws ag
the seats. This can damage the sea
needle tips.  
B
A
H
K
5. Fit the fuel screen (D) by using the h
a small screwdriver.  
6. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
7. Fit the needle valve (C) with lever arm, shaft  
and spring and tighten screw (H).  
8. Check, using or a ruler or the like, that the  
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve the  
correct settings.  
9. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
10. Carry out a pressure test. See page 100.  
98– English  
CARBURETTOR  
ZAMA C1Q-EL1  
Maintain a high level of cleanliness when  
reassembling the carburettor. Even small  
particles of dirt can cause operating  
problems.  
A
B
1. If the throttle and choke valves, shafts,  
lever arms and springs have been  
dismantled these must be reassembled.  
Lubricate the shaft bearings using a light  
oil.  
H
2. Fit the high and low jet screws and spring
NOTE! Do not tighten the screws against  
the seats. This can damage the seats an
needle tips.  
C
K
D
G
F
3. Fit the fuel screen (D) by using the handl
of a small screwdriver.  
4. Fit the pump diaphragm (G), gasket  
(F) and cover (E) on the pump unit.  
E
5. Fit the needle valve (C) with lever arm,  
shaft and spring and tighten screw (H).  
6. Check, using or a ruler or the like, that th
lever arm is level with the chamber floor.  
See the figure to the lower right. The lever  
arm can be bent if necessary to achieve  
the correct settings.  
7. Fit the control diaphragm (B) with gasket  
and cover (A) on the metering unit.  
8. Carry out a pressure test. See page 100.  
English – 99  
CARBURETTOR  
Pressure testing  
WARNING!  
The fuel used in the chain saw  
poses the following hazards:  
1. The liquid and its vapours are  
poisonous.  
2. Can cause skin irritation.  
3. Is highly inflammable.  
!
Pressure testing should be carried out with the  
carburettor fully assembled. Testing should  
always be carried out after the carburettor has  
been repaired, but a test can also be made for  
trouble shooting before dismantling.  
Make the test as follows:  
1. Set the high and low speed jet screws  
one turn open from the bottom.  
2. Connect pressure tester 502 50 38-01  
to the carburettor’s fuel intake.  
3. Lower the carburettor into a beaker of  
water.  
4. Pump up the pressure to 50 kPa (0.5  
bar) and clamp the pump tube with the  
spring clip.  
5. There should be no leakage. If a  
leakage occurs refer to the table below.  
Leakage on  
Diffuser jets  
Fault with  
Needle valve  
Pump diaphragm  
Leakage on the  
pulse tube  
Ventilation hole  
Control diaphragm  
above the metering unit  
Refitting onto chain saw  
Fit the carburettor to the chain saw and  
refit any other parts removed.  
For tightening torques, see the ”Service  
data” for the saw in question.  
Carburettor adjustment. See the operating  
instructions for the saw in question.  
100– English  
AIR FILTER  
Replace the chain saw’s air filter at the  
intervals stated in respective operating in-  
structions.  
It is extremely important that the air filter  
unitsonpowercutters268K,272Kandstump  
grinder 272S are maintained correctly. The  
air filter units on these models have there-  
fore been included in this workshop manual.  
268K, 272K and 272S  
A
The air filter system consists of:  
1. Prefilter.  
2. Main filter.  
Prefilter  
The prefilter is an oiled foam filter which is  
easily accessible under the filter cover (A).  
In dusty conditions this filter should be  
checked/replaced after every second  
refuelling.  
The filter should be cleaned and oiled regu-  
larly to obtain maximum filtration efficiency.  
Cleaning  
Dismantle the filter. Wash the filter in warm  
soapy water. After cleaning, rinse the filter  
thoroughly in clean water. Squeeze and let  
the filter dry.  
NOTE!  
Compressed air at a high pressure can  
damage the foam.  
Oiling  
Oil the filter carefully. It is extremely impor-  
tant that the entire filter is saturated with oil.  
Use HUSQVARNAoil no. 503 4773-01. The  
bottle holds 0.1l, which is sufficient for three  
applications.  
English – 101  
AIR FILTER  
Main filter  
The main filter is a paper filter and is accessible under the cover (B).  
This filter should be replaced/cleaned when the saw’s power de-  
creases or after 1-2 weeks. The filter is cleaned either by shaking or  
carefully blowing clean with compressed air. Note. The filter must not  
be washed.  
B
102– English  
TANK UNIT  
Dismantling  
WARNING!  
Empty the tank and dismantle the cylinder  
cover as well as the bar and chain.  
The fuel used in the chain saw  
poses the following hazards:  
1. The liquid and its vapours are  
poisonous.  
!
2. Can cause skin irritation.  
3. Is highly inflammable.  
Loosen the fuel pipe and disconnect the  
throttle cable if fitted.  
The figures on the next page illustrate all  
typesofmountingsbetweenthetankunitand  
the engine sub-assembly marked by letters.  
The mountings applying to the chain saw in  
questionisevidentfromthetableonthenext  
page.  
If heated handles are fitted remove the con-  
nections.  
The cable to the switch cannot be removed  
before the tank unit and the engine sub-  
assembly are separated.  
NOTE!  
Take care that the fuel pipe and throttle  
cable are not damaged.  
Dismantle the bolts as shown in the figures  
and the table on the next page and lift off the  
tank unit from the engine sub-assembly.  
Cleaning and Inspection  
Clean all parts and check the following:  
• That the fuel pipe is undamaged.  
• That the tank unit is not cracked.  
• That the throttle cable runs freely.  
• That the AV-system is undamaged For AV-  
system see page 107.  
• That the tank breather is not blocked or  
leaks.  
• That the fuel cap does not leak.  
• That the fuel pipe bushing seals  
• That the fuel filter is not blocked.  
If the fuel pipe needs to be replaced, meas-  
ure its length outside of the tank unit and  
makeanoteofthelength.Thisinformationis  
needed when fitting a new pipe.  
English – 103  
TANK UNIT  
A
B
C
D
E
L
K
J
I
F
H
G
Saw  
Bolts placed at  
Saw  
Bolts placed at  
36  
40  
41  
257  
262XP  
268  
A, D, F, K  
Has no tank unit  
A, D, F, K  
A, D, F, L  
A, D, F, L  
A, C, D, F, G, K  
42  
45  
51  
268K  
272XP  
272K  
A, D (under a cover) F, G, L  
Has no tank unit  
A, D, F, L (all under covers)  
A, C, D, F, G, K  
A, C, D, F, G, K  
A, C, D, F, G, K  
55  
61  
242XP  
272S  
281XP  
288XP  
A, D, F, L (all under covers)  
A, C, D, F, G, K  
A, D (under a cover) F, G, L  
A, C, D, F, G, K  
A, C, D, F, G, K  
A, C, D, F, G, K  
246  
254XP  
394XP  
3120XP  
A, D (under a cover) F, G, L  
A, D, F, L  
B, E, G, I, H  
C, D, F, I, J  
104– English  
TANK UNIT  
Assembly  
If a new fuel pipe is to be fitted proceed as  
follows:  
1. Measure the length of the old hose out-  
side of the tank unit, note the length.  
3. Twistthehosesothatittakesonthesame  
angle to the carburettor and let the hose  
protrude as much as the old hose did.  
4. Pull the hose through the filler hole using  
tool 502 50 83-01, cut off the bevelled end  
and fit the fuel filter.  
2. Oil half of the hose lightly and thread the  
oiledpartintothefueltankfromtheoutside.  
Fit the throttle and lock.  
NOTE!  
Ensure that the fuel pipe and throttle  
cable are not damaged.  
Fit the engine sub-assembly to the tank unit  
and at the same time insert the fuel pipe in  
the bottom of the carburettor space.  
If the saw has a throttle cable, insert this into  
the carburettor space too.  
The figures on the previous page illustrate all  
typesofmountingsbetweenthetankunitand  
the engine sub-assembly marked by letters.  
The mountings applying to the chain saw in  
questionisevidentfromthetableonthenext  
page.  
Make the handle heater connections if nec-  
essary.  
Fit the bolts as set out in the table on the  
previous page. Tightening torques, see the  
service data for the saw in question.  
Connectthefuelpipeandthethrottlecable to  
the carburettor.  
Fit the cylinder cover and the chain and bar.  
English – 105  
ANTI-VIBRATION SYSTEM  
Description  
The anti-vibration system reduces the vibra-  
tions which pass from the engine and cutting  
equipment to the handles. The anti-vibration  
system consists either of rubber elements or  
coil springs.  
The system’s movement limitation consists  
of side absorbers and/or stop screws.  
Dismantling  
The tank unit must be removed from the engine sub-assembly to access the anti-vibration system.  
See the previous pages.  
Saw 394  
Saws 40, 45 and 3120  
Other saws  
Remove the rubber element using re-  
spective tools as shown in the figure  
below.  
Release the catch on the plastic key.  
Slide off the spring and its holder.  
Remove the spring element using an allen  
key as shown below.  
106– English  
ANTI-VIBRATION SYSTEM  
Assembly  
Fit the rubber stop with the help of a wire or  
the like.  
Fittingtheanti-vibrationsystem’ssideabsorber.  
Fitting the anti-vibration system’s damper element. Tightening torques, see the ”Service data” for  
respective saws.  
Saw 394  
Saws 40, 45 and 3120  
Other saws  
Fit the rubber element using the tools  
shown in the figure below.  
Slide in the spring and its holder.  
Fit the spring element using an allen key as  
shown in the figure below.  
English – 107  
PISTON AND CYLINDER  
Dismantling  
Dismantle the following parts:  
• Cylinder cover. See operating instructions.  
• Spark plug. See operating instructions.  
• Carburettor.  
• Muffler.  
Saws36,40,41and45.  
Other saws  
On saw 394, disconnect the anti-vibration  
spring (A) from the cylinder.  
On all chain saws, undo the four cylinder  
bolts (B). The bolts are removed using a 4  
mm allen key (smaller saws) or 3/16” allen  
key (larger saws).  
Dismantle the insulation plate between the  
cylinder and the carburettor and the intake  
manifold.  
B
A
Remove the cables to the ignition coil.  
Remove the ignition coil.  
NOTE!  
Ensure that no dirt or other foreign  
particles fall into the crankcase.  
Saws 36 and 41.  
Saws40and45.  
Dismantle the tank unit.  
See page 102.  
Undo the four bolts under  
the crankcase.  
Carefully lift up the cylinder.  
Immediately cover the crankcase opening/  
crankshaft and crankshaft bearing with a  
paper or cloth.  
Remove one of the circlips on the piston  
push out the gudgeon pin and remove the  
piston.  
Remove the needle bearing from the little  
end of the connecting rod. Remove the  
decompression valve if fitted.  
108– English  
PISTON AND CYLINDER  
Cleaning and Inspection  
Clean all parts, scrape off any gasket  
residue remove carbon deposits from the  
following areas:  
1. The piston crown.  
2. The top of the cylinder bore.  
3. The cylinder exhaust port.  
4. The decompression valve channel.  
Check the following:  
1. That the cylinder’s surface coating is not  
worn, especially the upper part of the  
cylinder.  
2. That the cylinder is free of score marks.  
3. That the piston is free of score marks.  
See ”Faults and causes” on the next page.  
Small scratches can be polished off using  
fine emery paper.  
4. That the piston ring is not stuck into its  
groove.  
Max 1 mm  
5. Measure the piston ring wear by placing it  
in the bottom of the cylinder bore and  
measuring the gap and which should not  
exceed 1 mm.  
6. That the needle bearing is undamaged.  
7. That the intake manifold is undamaged.  
Pressure test the decompression valve as  
follows:  
1. Connect the tool 502 50 38-01 to the  
decompression valve  
2. Pump up the pressure to 80 kPa (0.8 bar).  
3. Wait 30 seconds.  
4. The pressure should not drop below 60 kPa  
(0.6 bar).  
English – 109  
PISTON AND CYLINDER  
Onsaws40and45,checktherubbersealing  
on the shaft seat. Change the shaft seat, if  
necessary.  
Faults and causes  
Score marks on the piston.  
1. Incorrect carburettor setting max. speed  
too high  
2. Too low octane fuel.  
3. Too little or incorrect oil in the fuel.  
Carbon build-up  
1. Incorrect carburettor setting max. speed  
too low.  
2. Too much or incorrect oil in the fuel.  
Piston ring breakage  
1. Excessive engine speed  
2. Piston ring worn out.  
3. Oversized piston ring groove.  
110– English  
PISTON AND CYLINDER  
Assembly  
NOTE!  
Ensure that no dirt or other foreign particles  
fall into the crankcase.  
Oil the needle bearing and fit it into the  
connecting rod little end.  
Refit the piston with the arrow facing the  
exhaust port.  
Slide in the gudgeon pin and fit the circlip.  
Other saws  
Saws 36, 40, 41 and 45  
Fit a new cylinder gasket  
Oil the piston and piston ring.  
Compress the piston ring either by hand or  
by using tool 502 50 70-01. Carefully fit  
the cylinder.  
Saws 36 and 41  
Applysiliconerubber50498  
26-01 to the lower crank-  
casehalf’scontactsurfaces.  
Check that the seals fit in  
their grooves correctly.  
Tighten the crankcase  
halves. Tightening torque  
refer to ”Service data”.  
Seecontinuationonnextpage.  
English – 111  
PISTON AND CYLINDER  
Other saws  
Saws36, 40, 41and45.  
Fit the four bolts under the crankcase.  
Tightening torque, see ”Service data”.  
Saws 40 and 45.  
Saws 36 and 41.  
Fit the tank unit.  
Fit the four cylinder bolts (B).  
Onsaw394,connecttheanti-vibrationspring  
(A) to the cylinder. The bolts are tightened  
using a 4 mm allen key (smaller saws) or  
3/16” allen key (larger saws).  
B
A
Fit the ignition coil and its cables.  
Fittheintakemanifoldandtheinsulationwall  
between the cylinder and carburettor.  
Fit the decompression valve.  
Carry out a pressure test as set out on the next page.  
Fit the following parts:  
• Cylinder cover. See operating instructions.  
• Spark plug. See operating instructions.  
• Carburettor.  
• Muffler.  
If a new piston or cylinder has been fitted the saw must be run-in for 3-4 hours with the carburettor  
set to the basic settings. See the operating instructions for the saw in question.  
112– English  
PISTON AND CYLINDER  
Pressure testing  
Decompression valve  
Test the decompression valve as follows.  
1. Connect the tool 502 50 38-01 to the  
decompression valve  
2. Pump up the pressure to 80 kPa (0.8 bar).  
3. Wait 30 seconds.  
4. The pressure should not drop below 60 kPa  
(0.6 bar).  
Crankcase and cylinder  
The following parts must be removed to  
pressure test the crankcase and cylinder:  
• Carburettor.  
• Muffler.  
Carry out the test as follows:  
1. Fit the cover plates (service tool) on the  
intake manifold and exhaust port.  
2. Connect tool 502 50 38-01 to the cover  
plate on the intake manifold.  
The decompression valve should be  
closed.  
3. Plug the opening to the impulse  
channel.  
4. Pump up the pressure to 80 kPa  
(0.8 bar).  
5. Wait 30 seconds.  
6. The pressure should not drop below  
60 kPa (0.6 bar).  
7. Leakage can occur from the  
decompression valve and the  
crankshaft seals.  
• Carburettor.  
• Muffler  
Fit the following:  
English – 113  
CRANKCASE AND CRANKSHAFT  
This section deals with the following:  
• Crankcase and crankshaft (describes how the  
whole assembly is dismantled and assembled).  
• Bar bolts (only describes replacing the bar  
bolts). See page 121.  
• Seals. Describes changing the seals without  
splitting the crankcase. See page 122.  
Dismantling  
Before the crankcase can be split the follow-  
ing must be removed:  
A. Chain and bar.  
D. Centrifugal clutch. See page 67.  
E. Oil pump. See page 70.  
F. Carburettor.  
See operating instructions.  
B. Starter. See page 57.  
G. Muffler. See page 49.  
H. Piston and cylinder. See page 108.  
C. Electrical system. See page 61.  
I.  
Tank unit. See page 103.  
Other saws  
Saws36,40,41and45.Seenextpage.  
Saw 394.  
NOTE!  
Ensure that no dirt or foreign particles  
enter the bearings.  
On saw 394, remove the carburettor  
chamber floor (A) and air jet (B).  
Other saws.  
A
B
Undo the bolts holding the crankcase to-  
gether. The bolts are on the clutch side.  
Note the location of the bolts that are of a  
different length.  
Split the crankcase using tool  
502 51 61-01.  
See continuation on next page.  
114– English  
CRANKCASE AND CRANKSHAFT  
Press out the crankshaft by using tool  
502 51 61-01.  
If necessary remove the crankshaft  
bearing from the crankcase.  
Proceed as follows:  
WARNING!  
The crankcase halves can be  
!
hot. Riskofburns. Wearprotec-  
tive gloves.  
Remove all rubber and plastic components  
from the crankcase halves.  
Saws 36 and 41.  
Saws 40 and 45.  
Heat the crankcase half in question to  
200°C.  
Wear protective gloves and knock the  
crankcase half gently, inside face down, on  
a wooden bench or the like, and the  
bearing will drop out.  
Split the shaft support and  
dismantle the halves.  
Fit the new bearing into the crankcase half  
while it is still hot.  
If the crankshaft bearing still remains on  
the crankshaft when dismantling, remove  
it using puller 502 90 90-01.  
Remove the bearing from the crankshaft  
using puller 502 90 90-01.  
If necessary remove the following parts:  
A.  
B.  
C.  
Chain tension screw  
Bar bolts  
Spike  
English – 115  
CRANKCASE AND CRANKSHAFT  
Cleaning and Inspection  
NOTE!  
Ensure no dirt or foreign particles  
enter the bearings, if fitted in the  
crankcase halves.  
Clean all parts and scrape of any gasket  
residue from the mating surfaces of the  
crankcase halves.  
Check the following:  
That the big end bearing does not have  
any radial play. Axial play is acceptable.  
That the big end bearing does not have  
any score marks or discoloration on the  
sides.  
That the little end bearing surfaces are not  
scored or discoloured.  
That the crankshaft bearings do not show  
signs of play, have an abnormal noise  
level and rotate smoothly.  
That the sealing surfaces on the  
crankcase seals are not worn and that the  
rubber has not hardened.  
That the crankcase is not cracked.  
116– English  
CRANKCASE AND CRANKSHAFT  
Assembly  
Saws 40 and 45.  
Other saws  
Saws 36 and 41.  
See page 120.  
Fit the bearing and seals on the crankshaft.  
Grease the seals.  
Continue assembly as described on  
page 111.  
WARNING!  
Thecrankcasehalvescanbehot.  
Risk of burns. Wear protective  
gloves.  
!
If the bearing needs to be fitted proceed  
as follows:  
A. Heat the crankcase half in question to  
200°C.  
B. Wear protective gloves, take out the  
crankcase half and press in the bearing.  
NOTE!  
Ensure that dirt and foreign particles  
do not enter the bearing.  
C.Let the crankcase half cool before  
continuing work.  
If new seals need to be fitted in the  
crankcase, grease the sealing surfaces  
and knock in the seals using respective  
punchs (see ”Service tools”).  
The seals can also be fitted when the  
crankcase is in position.  
Assembly position. See pages 123 and 124.  
Seecontinuationonnextpage.  
English – 117  
CRANKCASE AND CRANKSHAFT  
Other saws.  
Saw 40 and 45.  
NOTE!  
See page 120.  
Ensure that the connecting rod does  
not jam against the crankcase when  
the crankcase and crankshaft are  
assembled.  
Grease and fit a new crankcase gasket (A).  
Checkthattheguidepin(B)isinpositionand  
fit the other crankcase half.  
Using the assembly tool for the chain saw in  
question assemble the crankshaft in the  
clutch side’s crankcase half.  
Some saws have a sharp edge on the crank-  
shaft which can damage the seal. The as-  
semblysleeveshouldbeusedwhenworking  
on these saws. See ”Tools”.  
NOTE! Place the oil tank’s vent hose in  
the pocket above the tank cap in the  
equivalent crankcase half.  
NOTE!  
Continuing to pull with the assembly  
tool after the gasket is clamped will  
damage the crankshaft.  
Using the assembly tool for the chain saw in  
question, fit the two crankcase halves. Pull  
until the gasket is clamped between the two  
crankcase halves.  
Seecontinuationonnextpage.  
118– English  
CRANKCASE AND CRANKSHAFT  
Saw 40 and 45.  
Other saws.  
Fit the crankcase bolts. Tighten crosswise  
with the torque set out in the ”Service data”.  
Tighten the bolts closest to the crankshaft  
first.  
See next page.  
NOTE!  
Ensure excess gasket material does  
not fall into the crankcase.  
Cut off excess gasket at the level of the  
cylinder seating plane.  
On saw 394, fit the floor of the carburettor  
chamber using the four bolts.  
A
B
Fit the following parts  
D. Centrifugal clutch. See page 69.  
E. Oil pump. See page 77.  
F. Carburettor.  
A. Chain and bar. See  
operating instructions.  
G. Muffler. See page 49.  
B. Starter. See page 59.  
C. Electrical system. See page 63.  
H. Piston and cylinder. See page 111.  
I.  
Tank unit. See page 105.  
If a crankshaft has been fitted the saw must  
be run-in for 3-4 hours with the carburettor  
set to the basic settings.  
See the operating instructions.  
English – 119  
CRANKCASE AND CRANKSHAFT  
Saws 40 and 45.  
NOTE!  
Ensure that dirt and foreign particles  
do not enter the bearing.  
Fitthebearingonthecrankshaftbyusingthe  
assembly tool. See ”Tools”.  
Check the shaft seat’s sealing (A).  
Fit the shaft seat over the bearing and join  
the shaft seat at (B).  
A
B
Continue assembly as described on  
page 111.  
120– English  
CRANKCASE AND CRANKSHAFT  
Bar bolts  
When changing the bar bolts on all saws  
except 40 and 45 proceed as follows:  
1. Drain the chain oil.  
2. Knock through the old bar bolt so that it  
falls in the oil tank.  
3. Remove the bolt from the oil tank.  
4. Attach a steel wire to the end of the new  
bar bolts, thread the wire through the oil  
tank and out through the bolt hole in the  
crankcase.  
5. Pull the steel wire until the bolt comes  
out through its hole.  
6. Check that the bolt’s square shoulder is  
aligned with its recess in the crankcase.  
Turn the bolt if necessary.  
7. Pull through the bolt with its nut and  
spacer between the nut and crankcase.  
8. Refill with chain oil.  
English – 121  
CRANKCASE AND CRANKSHAFT  
Changing the seals  
This section describes how to change the  
seals without splitting the crankcase.  
Dismantling  
Before dismantling the seals remove the  
following parts:  
On the starter side:  
• Starter  
• Flywheel  
• Generator (if fitted)  
On the clutch side:  
• Chain and bar  
• Oil pump  
Seals fitted in the crankcase  
Use the dismantling tool for the saw in  
question and remove the seal as follows:  
1. Screw the tool into the seal’s rubber  
part.  
2. Pull the seal from the crankcase by  
turning the handle.  
Seals fitted on the oil pump or plastic flange  
Press out the seal using a suitable tool.  
122– English  
CRANKCASE AND CRANKSHAFT  
Assembly  
Seal assembly in the oil pump  
B
C
1. Place the oil pump on a sleeve (A) with  
an inner diameter greater than the  
seal’s outer diameter.  
2. Fit the seal (B) using the assembly  
punch so that the surfaces (C), are  
level.  
A
Seal assembly in the plastic flange  
1. Place the plastic flange on a flat and  
firm surface.  
2. Fit the seal using the assembly punch  
until it bottoms on the flange shoulder.  
Seal assembly in the crankcase  
Some saws have a sharp edge on the crank-  
shaft which can damage the seal. The as-  
semblysleeveshouldbeusedwhenworking  
on these saws. See ”Tools”.  
1. Fit the seal using the assembly  
mandrel.  
2. The seal should be fitted using the  
measurements for each saw as shown  
in the instructions on the next page.  
After fitting the seal assemble:  
On the starter side:  
• Starter  
• Flywheel  
• Generator (if fitted)  
On the clutch side:  
• Chain and bar  
• Oil pump  
English – 123  
CRANKCASE AND CRANKSHAFT  
Assembly positions starter side  
Measurement A should be as in the table below  
for resp. saws (Under the crankcase plane).  
A
61, 268  
272  
4-4.5 mm  
2 mm  
281, 288  
3.5 mm  
Measurement B should be as in the table below  
for resp. saws (Under the crankcase plane).  
B
42, 242, 246  
394  
1 mm  
5 mm  
3120  
0-0.5 mm  
51, 55  
1 mm above the  
crankcase plane  
1 mm  
Assembly position on the clutch side  
Measurement C should be as in the table below  
for resp. saws (Under the crankcase plane).  
C
51, 55 1 mm  
394  
0.5 mm  
254, 257, 262 1.5 mm above the  
1.5 mm  
crankcase plane.  
124– English  

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