Stihl FS 50 Service Manual

1Series 4144 Components FC, FS, KM
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© ANDREAS STIHL AG & Co. KG, 2008
RA_545_01_01_01
1. Introduction 2
2. Safety Precautions 3
3. Specifications 4
3.1 Engine 4
3.2 Fuel System 4
3.3 Ignition System 4
3.4 Tightening Torquese 5
4. Troubleshooting 7
4.1 Clutch 7
4.2 Rewind Starter 8
4.3 Ignition System 9
4.4 Carburetor 11
4.5 Engine 14
5. Engine 15
5.1 Removing and
Installing 15
5.2 Leakage test 16
5.3 Oil seals 16
5.4 Ignition Module /
Spark Plug Boot 16
5.5 Clutch 16
5.6 Flywheel 16
5.7 Motor 16
5.8 Muffler / Spark
Arresting Screen 19
5.9 Short Circuit Wire 20
5.9.1 Testing 20
5.9.2 Removing and
Installing
(Loop Handle Version) 20
5.9.3 Removing and
Installing
(Bike Handle Version) 23
5.9.4 Ground Wire 26
5.10 Ignition System
Troubleshooting 27
6. Rewind Starter 30
6.1 General 30
6.2 Removing and
Installing 30
6.3 Pawls 30
6.3.1 Carrier 31
6.4 Rope Rotor 32
6.5 Starter Rope / Grip 33
6.6 Tensioning the
Rewind Spring 35
6.7 Replacing the
Rewind Spring 36
6.8 ErgoStart 36
7. Control Levers 37
7.1 Switch Shaft /
Control Lever 37
7.2 Switch Positions 37
7.3 Interlock Lever
(Loop Handle) 37
7.3.1 Throttle Trigger 38
7.4 Throttle Trigger/
Interlock Lever
(Bike Handle) 40
7.5 Handlebar
(Bike Handle) 43
8. Fuel System 44
8.1 Air Filter 44
8.1.1 Baffle 44
8.1.2 Filter housing 44
8.2 Removing and
Installing
the Carburetor 45
8.3 Leakage Test 47
8.4 Servicing
the Carburetor 47
8.4.1 Metering Diaphragm /
Manual Fuel Pump 47
8.4.2 Inlet Needle 49
8.4.3 Pump Diaphragm 49
8.4.4 Throttle Lever /
Rotary Knob 51
8.4.5 Adjusting Screws 52
8.5 Adjusting
the Carburetor 54
8.5.1 Basic Setting 54
8.5.2 Standard Setting 55
8.6 Removing and
Installing Throttle Cable
(Loop Handle) 56
8.6.1 Removing and
Installing Throttle Cable
(Bike Handle) 58
8.6.2 Adjusting the
Throttle Cable 58
8.7 Removing and
Installing the Spacer
Flange 59
8.8 Tank Vent 60
8.8.1 Testing 60
8.8.2 Removing and
Installing 61
8.9 Fuel Intake 61
8.9.1 Pickup Body 61
8.9.2 Fuel Hoses 62
8.9.3 Fuel Tank Cap 63
8.10 Removing and
Installing the Engine
Housing 64
9. Drive Tube 65
9.1 Removing and
Installing 65
9.1.1 Disassembling
(KM 56) 66
9.1.2 Disassembling
(FC 56) 68
9.1.3 Disassembling
(FS 56) 69
9.1.4 Disassembling
(FS 40, 50) 70
9.1.5 Removing and
Installing the
Bearing Housing 71
9.1.6 Loop Handle 72
9.1.7 Loop Handle with
Barrier Bar 73
9.2 Add-On Components 74
9.2.1 Deflector for Machines
without Gearbox 74
9.2.2 Deflector for Machines
with Gearbox 74
9.2.3 One-part
Carrying Ring 75
9.2.4 Retainer 75
9.3 Gearbox 75
10. Special
Servicing Tools 76
11. Servicing Aids 77
Conte
nts

Stihl FS 50 Specifications

General

Engine Displacement	27.2 cc
Power Output	0.8 kW
Engine Type	2-stroke
Shaft Type	Straight
Starter System	Recoil
Overall Length	147 cm
Vibration Level	4.5 m/s²