MSF 4B Slipping in FWD

When accelerating forward on my 8’ rib, will almost get on a plane and then engine revs up, accelleration slows behaving like a spun prop. Changed out propeller and same situation. Recent history, engine was left in my aft cabin of my 42’ sailboat during both Cat 5 storms in PR. So I know based upon the inside mess the engine was tossed around. Just returned to my boat 1st of March and now in the USVI using the 8’ to run to shore. Engine appears to be OK visually and no weird noise when running. Changed out impeller and gear oil last July. No issues running around then so assumed putting the 4hp back on the water would be OK. Any advice to point me in the right direction would be appreciated.

Figured out the issue and its not related to the engine prop or gear vs the trim angle on the transom. I have no idea what has changed but when I adjusted the trim angle the cavitation stopped.

Yes, sounds like you were ventilating.