When I bought a bigger boat 3 yrs ago kept my 78 Glastron for my son that was in the Navy. Ran the boat once a year. Now he is out of the service but never took boat to Atlanta with him. I ran it on a hose yesterday and it sounded bad so I cleaned the carbs and tried to go run it today. Now it either has a worn prop bushing or something wrong with gears. 1978 model 85 Evinrude, revs up but doesn't move faster than idle speed. Am I safe to assume it's the prop bushing.