ms170 "rumble"

[walhondingnashua]

I put a new stihl bar and chain on my ms170. Its an older saw (10 years old or so) and has the 14" bar. When I free hand the chain around, it has a slight "rumble" to it. If I run the saw, it doesn't do it if I rev it up but when I put it to work, it has a constant rumble under load. Motor is running great and has all its power. Does not bog down either, just the "rumble."
The sprocket has some grooves worn in it. Could this be the cause?

 

[brenndatomu]

Yes, sprocket is worn, chain is not...they don't match...they must match. When you pull the chain around the bar by hand it should feel smooth.
Mismatched chain/sprocket is probably one of the most common un-diagnosed problems with the average persons saw

 

[walhondingnashua]

Thank you. Its a cheap fix from what I see so looks like I am ordering a sprocket.

 

[Deets]

Thank you. Its a cheap fix from what I see so looks like I am ordering a sprocket.

Get the needle bearing too

 

[walhondingnashua]

I think the kit I ordered comes with it.

 

[Sean McGillicuddy]

Does it look like this ..and not like this .

 

[walhondingnashua]

Yep that is what I am looking at, just not quit that worn.