Stihl av038 pull cord locks up / jams

[logwood]

Hi

I have a Stihl av 038.

When it pulls over it fires….

But it’s rare to be able to pull it over, because the pull cord locks up.

I have tried everything… flywheel ok, pull cord and assembly ok, piston and rings look intact from exhaust and carb port.

If I undo pull cord assembly and turn the flywheel with spanner it frees up again… untill it jams/locks up again.

Everything else is working. Good compression ect.

Even with spark plug removed… still locks up every rotation or other one.

What could it be? Tearing my hair out here. LolI’m 

[spudulike]

Break it down to parts, recoil cover, engine and clutch assembly. If the thing jams, if you remove the recoil cover, is it stuck. If you turn the flywheel clockwise, is it jammed, if it is, remove the spark plug, is the engine still jammed, if it is, remove the clutch and drum, is it still jammed? 

You need to work out which component is playing up. Possibly the carb is dumping fuel mix in to the crankcase causing hydro lock but the above will tell you where the issue is.

If the engine won't turn clockwise, will it turn anticlockwise? 

[skc101fc]

Nice methodology.  If we all followed this approach and worked out which component was failing each time, at least half of us wouldn't be on this forum, and the other half wouldn't have a mass of bits they'd forgotten how to put back together. 

 

[logwood]

It turns clockwise but gets jammed anti-clockwise (the way it jams when pull cord is pulled). I have not got the pull cord wrapped round wrong way or something silly??

 

I don’t think it’s hydro lock as it still gets jammed with plug pulled? Think hydro jam would not get jammed with plug pulled??

[organic guy]

I had one would not pull over because ignition coil was jamming the flywheel?

[spudulike]

I purchased a saw with a similar issue and it was a lump of carbon on the squish band. 

If the saw rotates anti clockwise, will it do a complete revolution?

Where is the piston when it locks up? 

[logwood]

I will check where it gets stuck and what direction ect…

 

but sometimes it pulls over. Then locks up again. So certain it’s an obstruction somewhere… when it has enough force before it gets stuck it passes through. But when it hits whatever it is I have to use force on the flywheel to free it again.

 

will get back to you after I have checked as this might help others too