I have a FOX Eagle III that I run as a Diesel. Last week I flew my plane fine, except that on the last flight it sagged and quit like it was suddenly very over compressed?? I had changed nothing and the exhaust was not terribly dark. Today the engine would not start? It would run briefly with more priming flips that usual and ONE ADDITIONAL turn of compression! Tonight I took the engine apart and found the ring is frozen in its grove with carbon. What can I soak the piston in to fix this?


Francis