prop size?

[Jonnie]

I have a 20' deck boat 2400 dry weight, 200 mercury outboard. It came with a 17 pitch prop, 14.25 diameter. It jumps out of the water. Pulls skiers easy and goes around 42-44 mph. I put a 19 pitch on , goes around 46 mph. Still has jump out of water. Both props allow me to run at 5800 rpms. Rev limiter. Both props are alumin. I want to try a 21 pitch to see what it will do. My buddy gave me one to try, the number on it reads 48 13700 A41 21P<br />Mine 48 13700 A46 19P<br /><br />What is the diff in the A41 and A46? <br />Is the one he gave me a different diameter? <br />Haven't tried putting it on yet because he has to ship it and I wanted to save some trouble of shipping if it's not going to fit.

 

[River Rat 01]

Re: prop size?

The diameters should be the same. You definately need more prop, I don't know the specific RPM range for your motor, but you don't want it going up against the rev limiter. You may even need more than the 21.<br />Good Luck,<br /><br /> RR01

 

[Wan Zai]

Re: prop size?

A good guide to selecting prop pitch is at www.mercurymarine.com . Look under technical info at mercury propeller. I try the calculator using 200 hp 2-stroke engine and 3000 lb boat [2400 boat, 400 lb engine, 200 lb load]. The calculator suggest 21 in prop. This size prop should be the starting point. Optimum WOT is still a trial and error but I hv use this calculator before and it hit optimum pitch versus weight 3 out of 3 time on 3 different boat set up.