Help me diagnose whirring/screeching noise from Stihl 088

[guydee]

Hi all,

I'm trying to diagnose this whirring/screeching sound at idle on my Stihl 088. It happens when the chain brake is both engaged and disengaged. I think it goes away as the RPMs increase, but it's hard to hear over the engine noise.

The easiest way to replicate the noise is by pulling the chain when the saw is not running (see video). Please note, I'm not referring to the metallic ringing of the clutch drum, but instead the whirr/screech.

I've pulled and cleaned the clutch assembly, replaced all the springs (one was broken when I got it). I've pulled the chain brake spring the surrounds the clutch drum and cleaned it (however it still may be close enough to be touching. I'm not sure what I can do to change that).

It still seems to make this noise and I can't see much online that sounds similar. Any ideas?

As for the saw... I recently picked up a deal at a local garage sale here in Australia.

I paid $130 aud for 1x Stihl 088 and 2x Stihl 066's (one red light, one regular). About 28 chains and 5 or 10 bars.

At least I think it's a 088. I think the plastic top cover has been cracked and the previous owner has riveted a piece of black plastic where the label used to be. It's significantly bigger than the 066 and looks similar to others I've seen online. Serial numbers don't match anything sold in Australia, I'm thinking they might've been brought here by the previous owner.

I've been tinkering with them to get them running as they should be and having a great time.

Thanks all

 

[J D]

Those saws were a steal at that...
Check for anything loose or rubbing. Did you replace the clutch needle roller bearing?
If it has the metal plate between the bar & the crankcase take that off temporarily & see if it still does it

 

[guydee]

I’ll try steal the bearing out of one of the 066 and see. Thanks for the tip. Will report back

 

[guydee]

I’ll try steal the bearing out of one of the 066 and see. Thanks for the tip. Will report back

 

[J D]

Pretty sure the 088 clutch bearing is bigger.
On inspection it's usually pretty clear if there's something wrong with them... the bearing only does anything when the clutch is not engaged, so if you can hear it when the clutch is engaged it will be something else

 

[stihltech]

Try lubing the sprocket bearing and also a smear on the sprocket washer.
Get a long screwdriver, or something similar. put it against the saw and up to you ear with the saw making the noise. Works like a stethoscope.

 

[jmwnc]

Make sure your oiler is engaging the clutch drum properly it’s a plastic gear behind the clutch with a metal spring/arm that indexes in a notch on the clutch drum.

 

[Tobystihl]

Mine does this, I believe it's the chatter of worn clutch shoes on the spider.

 

[huskydave]

I had one do this and it was fairly new, turned out to be a bad clutch bearing from the factory, this case I would check the shoes and springs. The big saws can be hard on clutch components.

 

[Gord404]

Had a 440 making a strange noise like that, after all was said and tried everything even a new seal it turned out to be loose bolts on the cylinder and the gasket was acting like a reed in a musical instrament- first time for everything.