Stihl MS 440 Service Manual

1MS 440, MS 440 C
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© ANDREAS STIHL AG & Co. KG, 2006
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 7
4.1 Clutch, Chain Drive,
Chain Brake,
Chain Tensioner 7
4.2 Rewind Starter 8
4.3 Chain Lubrication 9
4.4 Ignition System 10
4.5 Carburetor 11
4.6 Engine 13
5. Clutch, Chain Drive,
Chain Brake and
Chain Tensioner 14
5.1 Clutch Drum /
Chain Sprocket 14
5.2 Replacing the
Chain Catcher 15
5.3 Clutch 15
5.4 Chain brake 17
5.4.1 Checking correct
operation 17
5.4.2 Removing 18
5.4.3 Installing 20
5.5 Chain Tensioner 22
5.6 Bar Mounting Studs 23
6. Engine 24
6.1 Muffler / Spark
Arresting Screen 24
6.2 Leakage Test 25
6.2.1 Preparations 26
6.2.2 Pressure Test 27
6.2.3 Vacuum Test 27
6.3 Oil Seals 28
6.4 Removing the shroud 30
6.5 Cylinder and Piston 30
6.5.1 Removing 30
6.5.2 Installing 32
6.6 Piston Rings 35
6.7 Crankcase 35
6.7.1 Removing the
crankshaft 35
6.7.2 Installing the
crankshaft 38
6.8 Decompression Valve 43
7. Ignition System 44
7.1 Ignition Module 44
7.1.1 Ignition Timing 44
7.1.2 Removing and
Installing 45
7.1.3 Testing the ignition
system 46
7.2 Ignition Lead /
Spark Plug Boot 47
7.3 Flywheel 48
7.3.1 Removal 48
7.3.2 Installation 49
7.4 Stop switch 49
7.5 Wiring harness 49
7.5.1 Testing Wiring
Harness 50
7.6 Ignition System
Troubleshooting 51
8. Rewind Starter 54
8.1 General 54
8.2 Removing and
Installing 54
8.3 Pawls 54
8.4 Rope Rotor 55
8.5 Starter rope 55
8.5.1 Tensioning 56
8.6 Starter Rope Guide
Bushing 57
8.7 Replacing the
Rewind Spring 58
9. AV handle system 59
10. Single lever master
control /
handle system 60
10.1 Switch shaft 60
10.2 Throttle Trigger /
Interlock Lever 61
11. Chain Lubrication 62
11.1 Pickup Body /
Suction Hose 62
11.2 Valve 63
11.2.1 Cleaning 63
11.2.2 Replacing 63
11.3 Oil pump 64
11.3.1 Removing and
installing 64
11.3.2 Servicing 64
12. Fuel System 65
12.1 Air Filter 65
12.2 Carburetor 66
12.2.1 Removing and
Installing 66
12.2.2 Leakage Test 68
12.3 Servicing the
Carburetor 68
12.3.1 Metering Diaphragm 68
12.3.2 Inlet Needle 69
12.3.3 Fixed Jet 70
12.3.4 Pump Diaphragm 70
12.4 Adjustment (carburetor
without limiter caps) 71
12.4.1 Adjustment (carburetor
with limiter cap) 72
12.4.2 Basic Setting (carburetor
with limiter cap) 73
12.5 Tank Vent 74
12.6 Pickup Body 74
12.7 Fuel Hose 75
12.8 Tank housing 76

Stihl MS 440 Specifications

General

Displacement	70.7 cc
Chain Pitch	3/8"
Ignition system	Electronic
Starter	Recoil starter
Vibration reduction	Anti-vibration system
Weight (without bar and chain)	6.4 kg
Fuel tank volume	0.73 L
Oil Capacity	0.36 L
Guide Bar Length	40-63 cm
Guide Bar Length (recommended)	40-71 cm (16-28 in)