Stihl 029 Farm Boss froze up?

[rvincent]

I was up at the cabin this weekend cutting firewood with my new saw. Cut awsome for about 2 hours, then all of the sudden, it just froze and shut off right away. The chain turns, but the flywheel (pullcord) wont move. I took it apart a little and saw though the spark plug hole the piston was intacked, and it moved up then stopped. It will move up, then stop, move down then stop. I was moving it by turning on the clutch. It sounds like when it stops its hitting metal inside.

Did a wrist pin move out a little? Any other ideas? Anyone have this problem before.

[khouse]

was it brand new? what type and mix ratio were you using?

[rvincent]

it was used 2-3 times for an hour or so each time. I was using a 50:1 mix (stihl oil, 89 oct gas)

[khouse]

I have seen the cranks break if the chain sprocket is worn badly where the chain pops over a cog. Was it making a poping/jerking noise? After inspecting and removing the clutch and you still have issues - you'll have to tear it down to find the problem.