embpic1, knock on wood no engine outs so far, I really try and double check everything before I fly. My B25 is pretty heavy at 11.5 lbs so I am really dreading the engine out. Your engine problems sounds like it may be an airleak somewhere, that would explain why the needle valve doesn't have a lot of effect, check all of the seals and see if you can see if any exhaust or residue is around the cylinder head(leaky head gasket), there also could be dirt in the carb on that engine, but engine problems can be a very large pain and its hard to say. Good luck.

Michael