I have a great planes christian eagle 2 arf with a fuji 50 BT gas engine on it. This is what the review used and for some reason I cant get past 6600 RPM with my engine. The review stated they use a 20X8 prop and thats what im using. The only diff is they used a top flite 20X8 prop im using a master airscrew prop. The review stated they ran ar 7420 RPM and if i try and lean out the engine it bogs down and dies, so i kno wits not my high side adjustment. Any idea on this ?