Chain not moving when taut.

[bluehemisphere]

Thanks for the advice everyone.

 

Yes, the brake was off and yes, the chain was the right way round.

 

Have double checked the bar groove, and it's fine.

Nose sprocket is fine.

Chain runs freely around the bar when not attached to the saw.

 

Chain-wise, I actually bought a new chain and tried it but alas, same problem.

 

As Andy said, it could be an internal problem.

 

The drive sprocket spins fine under throttle when no chain is attached. But as soon as the chain is on there and taut, it won't turn.

 

SHOULD I be able to turn the chain by hand easily when it's taut? (I'm going for a 3mm gap at middle of chain tautness)

 

Dan, I can't see any needle bearing. Maybe I need to take the sprocket off. (Which I tried to do but the hex bolt holding it on is so tight I can't even budge it. Is it a left hand screw thread?)

 

Thanks again...

[Shane]

It may have a nylon drive cog between the motor and the clutch. Many years ago I had a B&D saw fail with this. It may be that the sudden jamming stripped some of the cogs on the nylon drive wheel (if they are still made like that) - so the chain and bar are OK but the engine will not drive the chain.

 

This may, of course, be complete bo11ox but worth a look.

[bluehemisphere]

Thanks Shane. I'll check that too...

[chrismechanic]

if you are within sensible driving distance from margate, pop round with it and ill have a look at it for you

chris

[TGB]

... SHOULD I be able to turn the chain by hand easily when it's taut?

 

Yes.

 

(I'm going for a 3mm gap at middle of chain tautness)

 

3mm is too tight. Lifting the bar with one hand, you should then be able to pull the chain away from the bar, so that the drive links under your finger pinch show a little air. And the chain then snaps back into the grove when released.

 

Dan, I can't see any needle bearing. Maybe I need to take the sprocket off. (Which I tried to do but the hex bolt holding it on is so tight...

 

Yes. It is a left-hand thread but you'll need to stop the piston moving. There's plenty if YT vids to show you how...

 

Does that make sense?

[peatff]

Does that make sense?

 

Not really. It's an electric saw

[chrismechanic]

[TGB]

A bit cheesy and somewhat lacking in PPE but you can clearly see the correct amount of adjustment. When he says the chain ought to be tight against the bar, he really means just snug. But watch through and you'll get the idea.

 

[morten]

Dan, I can't see any needle bearing. Maybe I need to take the sprocket off. (Which I tried to do but the hex bolt holding it on is so tight I can't even budge it. Is it a left hand screw thread?)

 

Yes, the bolt is likely a left hand thread. At least the sprockets on petrol saws are held on by left hand threads, and I don't see any reason why electric saws should be any different.