Stihl MS341 MS361 Chainsaw Workshop Manual
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STIH)
STIHL MS 341, 361 2004-05
Online version - not for reprint
1 MS 341, MS 361, MS 361 C
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© ANDREAS STIHL AG & Co. KG, 2004
Contents
1. Introduction 3
2. Safety Precautions 4
3. Specifications 5
3.1 Engine 5
3.2 Fuel System 5
3.3 Ignition System 5
3.4 Chain Lubrication 5
3.5 Tightening Torques 6
4. Troubleshooting
Chart 8
4.1 Clutch, Chain Drive,
Chain Brake,
Chain Tensioner 8
4.2 Rewind Starter 10
4.3 Chain Lubrication 11
4.4 Ignition System 12
4.5 Carburetor 13
4.6 Engine 16
5. Clutch, Chain Drive,
Chain Brake and
Chain Tensioner 17
5.1 Clutch Drum / Chain
Sprocket 17
5.2 Replacing the
Chain Catcher 18
5.3 Spiked Bumper 18
5.4 Clutch 19
5.5 Checking Operation
of Chain Brake 21
5.5.1 Removing and Installing
(without
QuickStop Super) 21
5.5.2 Removing and Installing
(with
QuickStop Super) 24
5.5.3 Brake Cable 28
5.5.4 Checking Play 28
5.5.5 Adjusting Play 29
5.5.6 Checking Operation of
Coasting Brake 30
5.6 Chain Tensioner 31
5.7 Bar Mounting Studs 32
6. Engine 32
6.1 Muffler/Spark
Arresting Screen 32
6.2 Shroud 33
6.3 Leakage Test 33
6.3.1 Preparations 34
6.3.2 Pressure Test 35
6.3.3 Vacuum Test 35
6.4 Oil Seals 36
6.5 Cylinder and Piston 37
6.5.1 Removing 37
6.5.2 Installing 39
6.6 Piston Rings 42
6.7 Crankcase/
Crankshaft 43
6.7.1 Removing 43
6.7.2 Installing 45
6.8 Decompression Valve 49
7. Ignition System 49
7.1 Ignition Module 49
7.1.1 Ignition Timing 50
7.1.2 Removing and
Installing 50
7.1.3 Testing the
Ignition Module 51
7.1.4 Ignition Lead /
Spark Plug Boot 52
7.1.5 Flywheel 53
7.2 Contact Spring 54
7.3 Testing Wiring
Harness 55
7.4 Ignition System
Troubleshooting 56
8. Rewind Starter 59
8.1 General 59
8.2 Removing and
Installing 59
8.3 Pawls 59
8.4 Rope Rotor 60
8.5 Starter Rope / Grip 60
8.6 Tensioning 61
8.7 Segment 62
8.8 Starter Rope Guide
Bushing 63
8.9 Replacing the
Rewind Spring 64
9. AV System 65
9.1 Repair 65
9.1.1 Spring between Front
Handle and Cylinder 65
9.1.2 Annular Buffer between
Tank Housing and
Crankcase 65
9.1.3 Spring, Annular Buffer
between Crankcase
and Tank Housing 66
9.1.4 Stop Buffer between
Crankcase and Tank
Housing 67
10. Master Control /
Handle System 67
10.1 Switch Shaft 67
10.2 Throttle Trigger /
Interlock Lever 68
10.2.1 Without
QuickStop Super 68
10.2.2 With
QuickStop Super 69
10.3 Front Handle 71
11. Chain Lubrication 71
11.1 Pickup Body /
Suction Hose 71
11.2 Valve 72
11.2.1 Cleaning 72
11.2.2 Replacing 73
11.3 Oil Pump 73
11.3.1 Removing and
Installing 73
11.3.2 Servicing 74
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2 MS 341, MS 361, MS 361 C
Contents
12. Fuel System 74
12.1 Air Filter 74
12.2 Carburetor 75
12.2.1 Removing and
Installing 75
12.2.2 Leakage Test 76
12.3 Servicing
the Carburetor 77
12.3.1 Metering Diaphragm 77
12.3.2 Inlet Needle 78
12.3.3 Fixed Jet 79
12.3.4 Pump Diaphragm 79
12.3.5 Accelerator Pump 80
12.4 User Adjustment 82
12.5 Basic Setting 83
12.6 Tank Vent 84
12.7 Pickup Body 85
12.8 Fuel Hose 86
12.9 Separating Crankcase
and Tank Housing 86
12.10 Replacing the Tank
Housing 88
13. Carburetor Heating 88
13.1 Testing 88
13.2 Troubleshooting Chart 90
14. Handle Heating
System 91
14.1 Troubleshooting 91
14.2 Testing
Heating Element
in Rear Handle 92
14.3 Removing and
Installing 92
14.4 Testing
Heating Element
in Front Handle 93
14.5 Removing and
Installing 94
14.6 Heater Switch 95
14.7 Generator 96
14.7.1 Troubleshooting Chart 97
14.7.2 Test Connections
and Test Values 99
14.8 Wiring Harness 100
14.8.1 Without Handle and
Carburetor Heating 100
14.8.2 With Handle Heating
System 100
14.8.3 With Handle and
Carburetor
Heating System 101
15. Special Servicing
Tools 103
16. Servicing Aids 105
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3 MS 341, MS 361, MS 361 C
This service manual contains
detailed descriptions of all the
typical repair and servicing
procedures for this power tool.
As the design concept of models
MS 341 and MS 361 is almost
identical, the descriptions and
servicing procedures in this manual
generally apply to both models.
Differences are described in detail.
You should make use of the
illustrated parts lists while carrying
out repair work. They show the
installed positions of the individual
components and assemblies.
Refer to the latest edition of the
relevant parts list to check the part
numbers of any replacement parts.
A fault on the machine may have
several causes. To help locate the
fault, consult the chapter on
"Troubleshooting" and the "STIHL
Service Training System".
Refer to the “Technical Information”
bulletins for engineering changes
which have been introduced since
publication of this service manual.
Technical information bulletins also
supplement the parts list until an
updated edition is issued.
The special tools mentioned in the
descriptions are listed in chapter
"Special Servicing Tools" of this
manual. Use the part numbers to
identify the tools in the "STIHL
Special Tools" manual which lists all
the special servicing tools currently
available from STIHL.
Symbols are included in the text and
pictures for greater clarity.
The meanings are as follows:
In the descriptions:
: = Action to be taken as
shown in the illustration
(above the text)
– = Action to be taken that is
not shown in the illustration
(above the text)
In the illustrations:
A Pointer
aDirection of movement
b 4.2
Reference to another chapter,
i.e. chapter 4.2 in this example.
Service manuals and technical
information bulletins are intended
exclusively for the use of properly
equipped repair shops. They must
not be passed to third parties.
Servicing and repairs are made
considerably easier if the clamp (1)
5910 890 2000 is used to mount the
machine on assembly stand (2)
5910 890 3100 so that one clamp
screw engages the outer 10 mm
hole (3) in the assembly stand.
To service the underside of the
machine (e.g. remove the front
handle), turn it upside down and
mount it so that one clamp screw
engages the inner 10 mm hole in
the assembly stand.
Pull the hand guard back against
the front handle for this purpose.
Always use original STIHL
replacement parts.
They can be identified by the
STIHL part number,
the STIH) logo and the
STIHL parts symbol (
This symbol may appear alone on
small parts.
1. Introduction
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4 MS 341, MS 361, MS 361 C
If the engine is started up in the
course of repairs or maintenance
work, observe all local and country-
specific safety regulations as well
as the safety precautions and
warnings in the instruction manual.
Gasoline is an extremely flammable
fuel and can be explosive in certain
conditions.
Improper handling may result in
burns or other serious injuries.
Warning!
Do not bring any fire, flame, spark or
other source of heat near the fuel.
All work with fuel must be performed
outdoors only. Spilled fuel must be
wiped away immediately.
2. Safety Precautions
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5 MS 341, MS 361, MS 361 C
3. Specifications
3.1 Engine
MS 341 MS 361
Displacement: 59.0 cm
3
59.0 cm
3
Bore: 47 mm 47 mm
Stroke: 34 mm 34 mm
Engine power to ISO 7293: 3.1 kW (4.1 bhp)
at 9,500 rpm
3.4 kW (4.6 bhp)
at 9,500 rpm
Max. permissible engine speed
with bar and chain: 13,500 rpm 14,000 rpm
Idle speed: 2,800 rpm
Clutch: Centrifugal clutch without linings
Clutch engages at: 3,500 rpm
Crankcase leakage test
at gauge pressure: 0.5 bar
under vacuum: 0.5 bar
3.2 Fuel System
Carburetor leakage test
at gauge pressure: 0.8 bar
Operation of tank vent at
gauge pressure: 0.3 bar
Fuel: as specified in instruction
manual
3.3 Ignition System
Air gap between ignition
module and fanwheel: 0.15 – 0.3 mm
Spark plug (suppressed): Bosch WSR 6F
NGK BPMR 7 A
Electrode gap: 0.5 mm
3.4 Chain Lubrication
Fully automatic, speed-controlled oil pump with rotary piston
Oil delivery rate: 5.5 – 15 cm
3
at 10,000 rpm
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6 MS 341, MS 361, MS 361 C
3.5 Tightening Torques
DG screws are used in polymer and light metal components. These screws form a permanent thread when they
are installed for the first time. They can be removed and installed as often as necessary without impairing the
strength of the screwed assembly, providing the specified tightening torque is observed.
For this reason it is essential to use a torque wrench.
Fastener Thread size For component Torque Remarks
Nm
Screw IS-M4x8 Chain tensioner cover plate/crankcase 3.0
Screw IS-M4x12 Brake band/crankcase 3.0 1)
Screw IS-P4x10 Brake cable retainer/tank housing 1.5 6)
Collar screw IS-M8x21.5 Collar screw for guide bar 23.0 1)
Screw IS-M4x12 Cover, chain brake/crankcase 3.0
IS-M10x1 Decompression valve 14.0
Screw IS-B4.2x9.5 Spark arresting screen/muffler 2.0
Screw IS-M4x12 Generator 3.0 1)5)
Screw IS-P5x16 Front handle/plug, AV spring 4.0
Screw IS-P6x19 Front handle/plug, AV spring 7.0 5)
Screw IS-P6x21.5 Front handle/tank housing, top right 7.0 3)
Screw IS-P6x32.5 Front handle/tank housing, top right 5.0 4)
Screw IS-P6x19 Front handle/tank housing, bottom 7.0 3)
Screw IS-P6x21.5 Front handle/tank housing, bottom 5.0 4)
Screw IS-M5x35 Handschutz/fan housing/crankcase 6.0
Nut M5 Shroud/stud, cylinder 3.0
Screw IS-P6x21.5 Chain catcher/crankcase/bearing plug 6.0
Screw IS-M5x16 Spiked bumper/crankcase 8.0
Screw IS-M5x12 Spiked bumper/crankcase/lock nut 8.0
Screw IS-M5x25 Crankcase, sprocket side/fan side 10.0
Screw IS-M5x16 Bearing plug/cylinder 10.0 2)
Screw IS-M5x20 Fan housing/crankcase 6.0
Carrier M12x1L Carrier/crankshaft 50.0
Remarks:
1) Loctite 243, medium strength
2) Loctite 270, high strength
3) aluminium
4) polymer
5) only version with handle heating
6) only version with QuickStop Super
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7 MS 341, MS 361, MS 361 C
Fastener Thread size For component Torque Remarks
Nm
Screw IS-M4x16 Annular buffer/crankcase 3.5 1)
Collar screw IS-P6x27 Annular buffer/tank housing 6.0
Screw IS-M5x16 Muffler/crankcase 10.0 2)
Screw IS-M5x16 Muffler/cylinder 10.0
Nut M12x0.75 Switch/handle housing 5)
Nut M8x1 Flywheel/crankshaft 33.0
Screw IS-M4x8 Side plate/crankcase 3.0
Screw IS-M5x8.5 Stud/cylinder 1.4 2)
Collar nut M5 Carburetor/collar screw 3.5
Screw IS-M5x25 Cylinder/crankcase 10.0
M14x1.25 Spark plug 25.0
Screw IS-M5x20 Ignition module/crankcase 8.0
Screw IS-M4x12 Oil pump/crankcase 3.0
Remarks:
1) Loctite 243, medium strength
2) Loctite 270, high strength
5) Version with handle heating only
Use the following procedure when refitting a DG screw in an existing thread:
Place the screw in the hole and rotate it counterclockwise until it drops down slightly.
Tighten the screw clockwise to the specified torque.
This procedure ensures that the screw engages properly in the existing thread and does not form a new thread
and weaken the assembly.
Note:
Power screwdriver setting for polymer: DG screws max. 500 rpm
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8 MS 341, MS 361, MS 361 C
4. Troubleshooting Chart
4.1 Clutch, Chain Drive, Chain Brake,
Chain Tensioner
Condition Cause Remedy
Saw chain stops under load at full
throttle
Clutch shoes badly worn Install new clutch
Clutch drum badly worn Install new clutch drum
Brake band stuck Check freedom of movement
and function of brake band.
Saw chain rotates at idle speed Engine idle speed too high Readjust with idle speed screw
(LA) (counterclockwise)
Clutch springs stretched or fatigued Replace the clutch springs or install
new clutch
Clutch spring hooks broken Replace the clutch springs
Loud noises Clutch springs stretched or fatigued Replace all clutch springs
Needle cage damaged Fit new needle cage
Clutch shoe retainer broken Fit new retainer
Clutch shoes and carrier worn Install new clutch
Chain sprocket wears rapidly Chain not properly tensioned Tension chain as specified
Wrong chain pitch Fit chain of correct pitch
Insufficient chain lubrication Check chain lubrication
Chain sprocket worn Fit new chain sprocket
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9 MS 341, MS 361, MS 361 C
Condition Cause Remedy
Saw chain does not stop
immediately when brake is
activated
Brake spring stretched or broken Fit new brake spring
Brake band stretched. worn or
broken
Fit new brake band
Clutch drum worn Fit new clutch drum
Saw chain does not stop
immediately when coasting brake is
activated (only versions with
QuickStop Super)
Brake cable play incorrect Readjust brake cable play (free
travel)
Brake cable stretched or broken Fit new brake cable
Parts of activating mechanism stiff Clean or replace parts of activating
mechanism
Chain brake spring stretched or
broken
Fit new brake spring
Brake ban stretched, worn or
broken
Fit new brake band
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What's Included?
Lifetime Access
Fast Download Speeds
Online & Offline Access
Access PDF Contents & Bookmarks
Full Search Facility
Print one or all pages of your manual
$30.99
The Stihl MS341 MS361 Chainsaw Workshop / Shop Manual provides comprehensive information for repairing and maintaining your chainsaw. Whether you are a professional mechanic or a DIY enthusiast, this manual covers all the essential details you need to know.
