Chainsaw Pull Cord Not Pulling

[Mass. Wine Guy]

I have a pretty old Jonsered 535 saw that still cuts well. Today the pull cord wouldn’t pull out. After removing the spark plug the cord pulled fine.

I’ve read that this could mean that the exhaust system is plugged up. I pulled (what I think is) the muffler off the front. What do I do now? I’m not at all a skilled mechanic and don’t know what to look for or how to fix it. I’m grateful for any advice.

 

[coffeebrk]

Piston should be smooth and shiny. Any vertical lines or scoring is bad. Post pic when you can

 

[Kenskip1]

How about the rope is worn and binding itself on the spool? Still cuts well? Then there is no no need to pull the muffler. With the plug removed there is no resistance and the rope works as designed. A possible crack on the rope pully could be a cause but this is a long shot.

 

[Mass. Wine Guy]

The round, horizontal thing I see when looking into the muffler opening? Looks smooth and shiny.

How about the rope is worn and binding itself on the spool? Still cuts well? Then there is no no need to pull the muffler. With the plug removed there is no resistance and the rope works as designed. A possible crack on the rope pully could be a cause but this is a long shot.

Maybe. But many YouTube videos suggest clogged exhaust if the cord pulls freely with the

 

[thompsoncustom]

piston looks good from what I can tell in the picture. How does it pull over with the exhaust off?

 

[Bill G]

What a thread........

 

[Mass. Wine Guy]

The cord won’t pull, even without the muffler. But does without the spark plug installed. Is this maybe an easy fix? I don’t want to spend a lot to take it in for repair.

 

[Captain Bruce]

I have a pretty old Jonsered 535 saw that still cuts well. Today the pull cord wouldn’t pull out. After removing the spark plug the cord pulled fine.

I’ve read that this could mean that the exhaust system is plugged up. I pulled (what I think is) the muffler off the front. What do I do now? I’m not at all a skilled mechanic and don’t know what to look for or how to fix it. I’m grateful for any advice.

Pull the recoil assembly, and re-build it? Its begging for service. The spark plug nonsense jostle simply bumped the stuck spool and it released.

 

[Mass. Wine Guy]

Not certain, but I think I see your point. But after re-installing the plug, the cord was still stuck.

 

[thompsoncustom]

What's the top of the piston and the spark plug look like? Is there so much carbon build up that the piston is contacting the plug?

 

[The Stig]

Did you change the spark plug before this ? Longer plug will hit the piston

 

[muddy42]

With the starter cord assembly removed, can you turn the flywheel and therefore the piston by hand?

If so the problem lies with the cord, spring or assembly. Even some WD40 can help temporarily, but otherwise easy to repair or replace.

If not, the piston and cylinder needs disassembling and looking at.

 

[Mass. Wine Guy]

The flywheel doesn’t turn very far unless I remove the spark plug.

 

[coffeebrk]

What plug are you using?

 

[muddy42]

At this stage, to diagnose the issue further, you need to get the cylinder and piston disassembled.

There could be something metal broken off and preventing smooth operation - a bit of broken piston ring, the needle bearing, crank, crank arm or circlip.

It could be lots of things but I’d suggest getting the cylinder off next.

 

[Mass. Wine Guy]

At this stage, to diagnose the issue further, you need to get the cylinder and piston disassembled.

There could be something metal broken off and preventing smooth operation - a bit of broken piston ring, the needle bearing, crank, crank arm or circlip.

It could be lots of things but I’d suggest getting the cylinder off next.

Circlip? Of course. I have no idea how to take it apart To a shop it goes.

The plug is an NGK #BPMR7A

 

[Bill G]

Circlip? Of course. I have no idea how to take it apart To a shop it goes.

That would be your best bet

 

[The Stig]

Is the washer on the spark plug ?

 

[Mass. Wine Guy]

Is the washer on the spark plug ?

Yes. Washer is on.

 

[The Stig]

Yes. Washer is on.

Sure it’s not hitting the plug ? Screw it all the way in and back it out 1 turn and see if that works