hi to you all, i finally finished my first spad plane ,put the engine in and started tuning,and there started the problems: at first i had bubbles in the fuel line ,after asking some people i found out that the vibration caused them so i've put some foam between the fuselage and the tank and they stopped! so today i started tuning the engine .as i was playing with the rpm i decided to test the up and down of the plane. with full throttle i've pointed the plane down and then up slowly and it stopped! any ideas?my engine is a os 40 .thanks