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.