Correct Prop Size?

[duckhunter55]

Okay I have a 1983 25hp Chrysler motor, on a 2006 16ft. aluminum modv jon boat. My question is what would be a good prop size and pitch for this motor? It will be pushing 2 batteries, gas taank probly 2-3 people and decoys for duck hunting, Probably aroungd 800- 900 lbs , not including motor. currently have a 10 3/8 x 13 1/2 in prop on it. Any help greatly appreciated, thanks

 

[Silvertip]

Re: Correct Prop Size?

Without any wide open throttle rpm and speed information with your current prop your guess is as good as ours. Since you very likely have neither a tach or a speedometer, and hence no base line, we (at least I) have nothing to go on. The proper prop is one that allows the engine to run at the top of its maximum recommended wide open throttle rpm band with the load you normally carry. Too much pitch lugs the engine and that's not good. Too little pitch causes the engine to over rev and that's not good. If you have an overwhelming need to optimize this setup, consider adding a "Tiny Tach". Borrow a GPS or have someone run along side for speed and RPM measurements at WOT. Then post back.