ORIGINAL: micool72
I need help with my engine , it does not like nitro i run 5% in it flys fine but wont drop back to idle for agers sits there barking at me and is very hard to tune does not peak before going lean have been trying different top and bottom end tuning with no result oil is also black coming out exhaust this is a new motor with about 20 flights , pulled it down today every thing seems ok inside.i have two other planes and none of them give me any problems
please help with some tips please.
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It sounds as though someone either forgot to put in the head gasket, or they removed it before you got to it. The engine sounds over compressed. I would check to see that there is a head gasket (shim) in place. And I wouldn't run it much as it is until I knew one way or the other.
Highly over compressed engines will never get to their peak rpm because the timing is too far advanced.