Chainsaw will not crank over

[Dex]

Stihl 031 av cranks and pull rope extends fully when spark plug is removed. Once spark plug is put in and the saw has compression the saw will not crank. Pull rope comes out about 6 inches on the first pull and stops. on each additonal pull the saw cranks less until it nearly locks up

 

[Lawnranger]

Remove the muffler and try again. I have had plugged mufflers/spark arrestors cause all kinds of starting/running problems. If the engine starts and runs with the muffler removed, you have obviously found the problem but do not run the engine for very long without the muffler installed.

 

[chance123]

Make sure you have the correct spark plug in it. I have seen these come in with long reach plugs and the piston kisses the spark plug not allowing full rotation

 

[EngineMan]

Stihl 031 av cranks and pull rope extends fully when spark plug is removed. Once spark plug is put in and the saw has compression the saw will not crank. Pull rope comes out about 6 inches on the first pull and stops. on each additonal pull the saw cranks less until it nearly locks up

wrong spark plug or too much compression, take plug out and put your finger on the hole, can you now pull it over...?

 

[DaveTN]

Stihl 031 av cranks and pull rope extends fully when spark plug is removed. Once spark plug is put in and the saw has compression the saw will not crank. Pull rope comes out about 6 inches on the first pull and stops. on each additonal pull the saw cranks less until it nearly locks up

I've seen chainsaws nearly break your arm and jerk the rope handle out of my hand with such force it would nearly take off skin!! What the problem was turned out to be a partially sheared flywheel key. That could be the problem. You can remove the cover and the flywheel nut and visually inspect the keyway and see if the key is sheared any. Hope this helps. Dave

 

[chance123]

I've seen chainsaws nearly break your arm and jerk the rope handle out of my hand with such force it would nearly take off skin!! What the problem was turned out to be a partially sheared flywheel key. That could be the problem. You can remove the cover and the flywheel nut and visually inspect the keyway and see if the key is sheared any. Hope this helps. Dave

Very true. On some of the Still products, the FW key is actually part of the FW itself. They make you purchase a flywheel, just because the key is sheared.