I have a 2002 Passage 456 , yanmar 4jh3-te 75 hp turbo engine and have installed a 3 blade flexafold folding prop 20-14 and we are told we are over propped,(tell tale blue Ish white smoke, and oil dripping from air breather) flexafold says no, diesel mech says yes, if someone has the same boat and same prop and can get 3600 rpm in forward under load I would like to know, I cannot get more than 3200 rpm in forward, can get 3809! In reverse and 4000 in neutral.