Let's assume that the clutch was overhauled correctly. Perhaps the problem with the clutch might have been caused by the system after it namely:
bent drive shaft
drive shaft not reinstalled in alignment(maybe there might have been a shim in there)
worn cutless bearing (that's what caused my vibration)
poorly aligned propeller
worn or poorly installed stuffing box
All of these can cause vibration and some will resonate at particular frequencies.
try these before you get an expert:
pull on the shaft side to side and see if there is wear in the cutless bearing
undo the bolts holding the shaft to the gearbox
(warning, the shaft might slide out) now rotate the shaft and see if there are any tight spots as it turns (maybe a bent shaft)
reinstall shaft, rotate it and measure from a fixed point on the hull
to a similar point on each propeller blade. Check distance and angle. This MIGHT show a bent blade.
It will be complicated to do any work while the boat is in the water
. You might consider a total rear end replacement. but remember that all of this assumes that the clutch overhaul
was done correctly.