Hi guys, well I've been flying the Kitfox 4 that I finally finished, and have a question. My engine is a 912 80 HP with about 120 hours on it. When I pull power back when I enter the pattern, I get a fair amount of shaking between about 3000-4000 RPM. Smooth above and below those RPMs. Haven't noticed it as the engine spins up, but then I'm pushing in the throttle faster then I pull it back when entering the pattern. I have a 3 blade 72" IVO ultralight prop. I think I have read others mention this, but don't remember the possible reasons. Anyone care to offer an opinion? Thanks, JImChuk