Hobbsy
I think you are right on about the Yahama. That happened more years ago than I want to admit to!! On your comment about more nitromethane....it's seems strange to me that OS recommends 20% nitro, 20% oil fuel for the supercharged engine that is prone to detonation. Wouldn't you think lower nitro content would be better, all other things being equal? I agree the higher nitro fuel is going generate more power and therefore more heat in the engine, but nitromethane has a slightly higher octane rating than methanol and shouldn't knock as easily, right??? I am still in the break-in mode with the supercharged engine and experimenting to find the best fuel for this prop size. I am adding 3% castor to all fuels I'm trying in that engine until it is well broke in. Anybody got any suggestions on fuels for high load conditions such as overpropped 4 stroke engines (other than don't do it)???