Okay, I decided to try a 20x8 prop same type MA and this thing is really coming on. I got 9,000 rpm on the tach. and even if it's off some I doubt it's off that much. I have some vibration but I think that is to be expected with a 4-stroke and I haven't balanced this prop and I think it's still breaking in. I may still try a 11mm Walbro WT391 carb but the bottom line is this engine likes less air and more fuel. Oh, the best part is one or two flips and popps and she's running. Almost sounds like a real LeRhone. To be continued....