ORIGINAL: matador_24

well, if it's leaking too much, I don't think it's a tunning problem, specially it was running good before, do what ken said, check out for the gaskets and all the bolts, maybe they are not properly tighted, if that doesn't solve the problem, you should consider replacing it, I know it's possible to fix an engine but if you are not very familiar with the motors, maybe it's better to get a OS32 or OS37 (this one is much better), I personally had a TT39, starting to have tunning problems, a bearing broke after, I just replaced it with an used OS32 and my heli is alive again, you will be surprised how easy is to tun OS engines and how well they perform....