Hello, I have a 1984 24 ft rampage express with a 5.7 300 hp I /O alpha 1 .. Currently I am running a 14 1/2 x 17 3 blade . I can only get the boat rpm to 4100 @ 28.5knots. It will cruise at 19 knots @ 3400 rpm burning approx 1 gal per mile. Which seems very bad for economy. I also have a hard...
