I have a 1985 85 hp force outboard on a 15 ft mfb caprice. 650lb hull, 300ish motor, plus gear. I have a 13x17 prop on it I can trim all the way out without the prop blowing out. Is my motor set too deep or do I need a bigger prop? I can get 5600+ rps out of it with me, my gf, fishing gear, and...