How can you tell if your prop is out of balance? Would you notice it more at higher rpm vs. lower rpm? The reason I ask is because I am at a dead end. I have performed everything I can think of but my 80hp Rotax UL still idles rough and makes massive gearbox ratcheting noises below 2500 rpm. I am wondering if my prop is out of balance/and or bent. However- It runs smooth from 2500 on up all the way to 5200, so in my mind I am thinking if the prop was bad it would get worse at higher rpm- not better. I had the gearcase rebuilt so that takes it out of the equation, and the engine only has 150 hours since new. I know the original owner ground looped the plane so I have a lot of unanswered questions. Any input would be appreciated-

Thanks,

Scott