On a typical OS engine, 1/4 turn rich of peak on the high speed is too much. That probably put you over 1000rpm down and has it running very rich. Conditions vary but often 3-4 clicks back from peak is enough to get the recommended 300rpm rich sweet spot.

As others said you MUST learn to tune your low end also. The throttle response will improve drastically, fuel consumption will decrease drastically, and it will make your plane easier to land as you can hold a much lower reliable idle. Most engines Ive owned - OS included - are typically off a full turn (or more) too rich on the idle from the factory.


Well cared for most RC engines will outlast us. Ive got a 10 year old 46FX that has been on at least 5 different planes and probably had 30+ gallons through it. Right now its screaming at 16k rpm on a 120mph Q-500 ship I have a number of Saitos that have similar usage, some on their second or third set of bearings but otherwise they run like new.