2 cyl, 2 stroke with big foot. I need to find my RPM, I cant even pull someone on a tube with my boat!!!!!!!!!! Cannot handle a load whatsoever. The boat is a 16ft old fiberglass runabout. 2 ppl in the boat is ok, 3 runs bogs and no speed, and cant plane. Running a 13 3/4x15 prop now. I know...