Alpha vibration

[nobodyjeff5888]

Big problem! Had to replace motor in 1988 welcraft . 350 magnum. New prop. Heavy vibration under load.won't go above 2000 rpm..no vibration in neutral will Rev to 4000 no problem. Purrs like a kitten at idle. Been told to do alignment check. Any other ideas? Been working on this since beginning of season. Any help will be greatly appreciated thanks in advance

 

[nola mike]

If you haven't checked alignment after engine replacement, that would be the first step

 

[Bt Doctur]

Bad alignment by itself would not normally cause a loss in rpm. firing order checked? dead plug, dead plug wire,

 

[achris]

What Bt said, then pull the prop and look at the front labrinth seal area and the coresponding surface on the gear housing. See any rub marks? (you shouldn't)...
But I do feel this is an engine problem, not prop. And you should have done an engine alignment on replacing the engine.

Chris....