372xp basket case

[Norm Raffelson]

Hey Guys I recently replaced the top end on an older 372xp I thought I had seized the piston. When I removed the head I broke the rings. As a quick fix I bought a head piston assembly and attached. When I went to fire it up it started and ran. Quite loudly then shut down. Flywheel seems to have locked up. I took the plug and the pull start off and shot some wd40 in the head to lube it and manually turned it over it keeps seizing up in different spots then it would turn over freely then lock up again. Is this a bearing issue??

 

[ironman_gq]

Sounds like a crank bearing went out, clutch side is most common but it could be either could also be the big end bearing on the crankshaft which is non-servicable. Probably have bad crank seals as well if the bearing is shot.

 

[cuinrearview]

A broken ring is also a possibility. No way of knowing until shes torn down. Good luck! There are lots of folks in the chainsaw section that will answer questions.

 

[ironman_gq]

Is it possible that the piston was installed backwards?

 

[CLASSIIILVR]

+1 for broken ring hang up!