unusual prop engine/boat/drive question

[ltgesq]

I have an excellent condition 71 starcraft holiday aluminum runabout that has an original pre-alpha sterndrive. The 120 horse 2.6 liter engine was replaced with a rebuilt 3.0 engine and the exhaust was routed through the transom on the left side rather than through the prop center.

At some point the prop was replaced and the engine no longer is the speed machine it was with the 120. Instead of the 42mph i used to clock, i am lucky to see 33 with an empty boat. With a full boat the engine overrevs to 5k and barely hits 30. the prop wizards suggest a 14 1/4 x 21. Is this where I should start?

i'd like to ski behind this thing but i weigh nearly 250 these days. Any suggestions(besides losing weight)?

 

[Silvertip]

Re: unusual prop engine/boat/drive question

On one hand you want speed and on the other you want to ski which means those activities require props on both ends of the performance spectrum. Since you didn't tell us what prop you have now we can only guess that it is something less than 21P. Also, since the engine tends to over rev at WOT, I would suggest you retain that prop for skiing. For speed, determine what prop you have now and then increase pitch one inch for every 200 rpm you are over the upper end of the recommended WOT rpm. If you prop for speed you will have a tough time getting your behind out of the water.