Re: Prop washer problem
Do you have a small hub prop on the large hub gearcase (old BassBoat trick)? I'm thinking the prop is way off balance, or you're using the wrong thrust washer with the wrong prop. Yamaha factory props need a thrust hub with a collar on the inside diameter of it that fits into a pocket on Yamaha props. Most other props use different thrust washers without that collar. Some even have that collar on the outside diameter.
What I'm thinking is a prop imbalance otherwise. It could be weight imbalance or pitch imbalance. One blade might not be at the same pitch as the others. If you haven't had the prop checked yet, maybe you should.
Give the prop a spin and watch the center of the propshaft. If you see it wobble, there's your answer. Generally if a propshaft is bent enough to see, it's way beyond spec and needs to be replaced. UNofficially if you can't see it, it ain't worth worrying about on your average outboard. But on a High Hp motor like that, you need to be within spec.
