[Putershark]

I agree with Dick and like I tell most people, whatever the plate says for max grunt (HP) is what you should hang on it

Boats don't "coast" very far (unlike your car) as you well know when you let off the power... And I would much rather have the larger HP engine not working as hard to push it, then a smaller engine working harder and many times burning more fuel (running @ higher RPM) to run the same ground speed due to having to use a smaller pitch prop.