ORIGINAL: Korps
Just spoke too the guy at the hobby shop who had a look at my plane. The feedback was as follows:
They set the low and high end needles and made it a bit on the rich side - he said he feels safer with the engine like that because as soon as the engine gets hot it seems as if there is no pressure/back pressure in the exhaust (Apparently this could be that the engine got too hot at a stage). They tested the engine in the yard and it's working fine now..He said the engine will tend too rev higher when the plane pitches up - but that is the way it should be he says. When flying level and straight it will fly on a more of a rich setting. Apparently the exhaust was a bit loose (but I think it was because of the nose dive it took into the earth). Apparantly (I think he said exhaust gasket) was also broken - don't know if this was before or after the "crash".
They are going too maiden the plane hopefully this weekend. I'm hoping for the best.
Glad it's working right. If it's been running lean, it will have overheated and worn the internals more than normal but it should still be fine - you might have shortened it's life a little is all. Engines will usually speed up slightly when they pitch up - harder for fuel to get to the carb, so the mixture leans out slightly (that's one of the reasons to run it slightly rich normally). A leaking exhaust will only make a bigger mess of your plane - shouldn't affect performance too much (unless it's a really bad leak - that would reduce your tank pressure). Exhaust gaskets are a waste of time - when the engine's running the vibration & heat compress the gasket which make the exhaust loose, then the gasket tears and falls out. Generally mufflers seal up to the engines just fine without a gasket - if you want you can use a little high temp RTV silicon to help seal it.
Good luck with the maiden - let us know how it goes.
