Troubleshooting

8.1 Troubleshooting

The different faults which may occur on the chain saw are divided into four groups. Within each group possible operating faults are listed to the left while the probable fault alternatives are listed to the right. The most likely fault is listed first, etc. See separate instruction for Autotune troubleshooting.

Starting

Difficult to start

Air filter blocked

 

Choke does not work

 

Worn choke axle

 

Worn choke valve

 

Blocked fuel filter

 

Blocked fuel line

 

Piston ring is stuck

 

Blocked impulse channel

 

 

The carburettor

Loose or faulty fuel pipe

leaks fuel

Hole in diaphragm

 

Worn needle/needle tip

 

Control system sticking

 

Control system set too high

 

Leaking control system

 

(air or fuel)

 

The cover on the carburettor

 

pump side is loose

 

 

Floods when the

Worn needle/needle tip

engine is not

Control system set too high

running

Control system sticking

Idling (low speed)

 

 

 

Does not idle

Leaking inlet hose (rubber)

 

Loose carburettor mounting

 

Loose or faulty fuel pipe

 

Blocked fuel filter

 

Blocked fuel line

 

Tank ventilator blocked

 

The throttle valve shaft is inert

 

Throttle stay is binding

 

Defective throttle return spring

 

Bent valve axle stop

 

Faulty diffuser jet

 

 

Too rich idling

Worn needle/needle tip

 

Worn lever arm in the control

 

system

 

Leaking diaphragm/cover plate

 

 

Idling (low speed) (continued)

 

Worn needle/needle tip

 

Leaking diaphragm/cover plate

 

Worn lever arm in the control

 

system

 

Faulty diffuser jet

 

 

Uneven idling

Blocked fuel filter

 

Blocked fuel line

 

Leaking inlet hose (rubber)

 

Loose carburettor mounting

 

Worn throttle valve axle

 

Loose throttle valve screw

 

Worn throttle valve

 

Leaking control system

 

(air or fuel)

 

The control system’s centre

 

knob is worn

 

Hole in diaphragm

 

Leaking diaphragm/

 

cover plate

 

Leaking crankcase

 

 

 

Blocked fuel line

 

Leaking control system

 

(air or fuel)

 

Leaking diaphragm/cover plate

 

Faulty diffuser jet

 

Leaking crankcase

 

 

Too much fuel at

Worn needle/needle tip

idle speed

Leaking diaphragm/

 

cover plate

 

 

English - 57

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Image 57
Husqvarna 966451906 manual Troubleshooting, Starting, Idling low speed