Operation Manual
1MS 241 C
q
© ANDREAS STIHL AG & Co. KG, 2011
RA_741_00_01_01
1. Introduction and
safety precautions 3
1.1 Introduction 3
1.2 Safety precautions 4
2. Specifications 5
2.1 Engine 5
2.2 Fuel system 5
2.3 Ignition system 5
2.4 Chain lubrication 5
2.5 Tightening torques 6
3. Troubleshooting 8
3.1 Clutch 8
3.2 Chain Drive,
Chain Brake,
Chain Tensioner 9
3.3 Chain lubrication 11
3.4 Starter 12
3.5 Ignition system 14
3.6 Carburetor 15
3.7 Engine 18
4. Clutch 19
4.1 Clutch drum 19
4.2 Clutch 19
5. Chain brake 20
5.1 Checking operation of
chain brake 20
5.2 Brake band 20
5.3 Brake lever 21
5.4 QuickStop Super
brake lever 23
5.4.1 Adjusting brake cable 25
5.4.2 Brake cable
Removal and
installation 27
5.5 Cam lever 28
5.6 Pins 29
5.7 Chain tensioner 31
5.7.1 Quick chain
tensioner 31
5.7.2 Chain catcher 32
5.8 Bar mounting stud 32
5.9 Collar nut for chain
sprocket cover 32
6. Engine 34
6.1 Muffler 34
6.2 Leak testing 35
6.2.1 Preparations 35
6.2.2 Vacuum test 36
6.2.3 Pressure test 36
6.3 Oil seals 37
6.3.1 Ignition side 37
6.3.2 Clutch side 37
6.4 Shroud 38
6.5 Cylinder 39
6.6 Crankshaft 41
6.6.1 Ball bearing /
crankcase 46
6.7 Piston 47
6.8 Piston rings 49
6.9 Decompression valve 50
7. Ignition system 51
7.1 Ignition timing 51
7.2 Pre-separator 51
7.3 Control unit 51
7.4 Spark test check
control unit 54
7.5 Spark plug boot 55
7.5.1 Ignition lead 56
7.6 Flywheel 56
7.7 Short circuit wire 57
7.7.1 Contact test 57
7.7.2 Removal and
installation 57
7.7.3 Ground wire 64
7.7.4 Contact spring 64
7.8 Troubleshooting,
ignition system 66
8. M-Tronic 69
8.1 Calibrating the
control unit 69
8.2 Testing 70
8.2.1 Test preparations 70
8.2.2 Connect the test lead 70
8.2.3 Check screwed and
plug connections
as well as switch 70
8.2.4 Checking the
solenoid valve 72
8.2.5 Checking the start
detection function 73
8.2.6 Checking the wiring
harness 74
8.3 Wiring harness 76
8.4 Switchgear 76
8.5 Troubleshooting,
M-Tronic 80
8.5.1 Engine does not start 80
8.5.2 Engine does not start
in position } 81
8.5.3 Engine speed drops
under load
– low power 82
8.5.4 Ignition –
no ignition spark 83
8.5.5 Engine stops
suddenly 84
8.5.6 Cut-off speed
not reached 85
9. Rewind starter 86
9.1 General 86
9.2 Fan housing 86
9.3 Pawls 87
9.4 ErgoStart 88
9.5 Rope rotor 89
9.6 Starter rope /
starter grip 89
9.7 Tensioning the rewind
spring 90
9.8 Replacing the rewind
Spring 91
Contents