[kd3pc]

sounds like an out of balance shaft or prop, alignment - if done correctly, should be good across the operating range.

You can turn the shaft coupling 90 or 180 degrees, after marking it, to see if the problem changes or have a reputable shop check the prop and shaft.

Assuming it did NOT happen prior to the repair? Loose mount?

 

[kd3pc]

I've no idea if the couplings on transmission and prop shaft were reconnected with the same holes matched up .... sounds like that might be a possible thing worth trying? That is, rotate shaft 90 degrees and rebolt. Do again etc to see if one position is good .... as you see I'm no expert!

thanks, JohnB40

Yes, mark the "current" position, and then rotate the shaft 90 degrees at a time.