I have a 79 J30 with the 2QM15 engine. What is a good crusing engine rpm and what is the max rpm one should run at. How much fuel for each is used per hour and what is your boat speed. Also what the the shaft diameter. What is a good way to determine how much fuel is in the tank (no gauge) or do you keep track via engine hrs. If so how much fuel is used as per the engine hr gauges.
