What prop size for Yamaha 150 on Wahoo 21 CC?

[mhadden]

Anybody have an opinion on what size prop to run? Just bought the motor without a prop and need to size up the situation so I can get out on the water! <br />Thanks.

 

[gw204]

Re: What prop size for Yamaha 150 on Wahoo 21 CC?

I've got a 150 Merc. on a 20' Grady and I'm currently spinning a 14 x 17 SS. The most important thing is to prop it so the motor can reach the upper end of it's WOT rpm range (probably 5000 to 5500) when the boat is loaded with the no. of persons, fuel, gear, etc. that you will normally run it with. My prop let me spin up to 5800 which is a little too much so I'll probably be dropping back to to a 14 x 19. I believe Merc. props will fit Yamaha motors. Merc. has a prop demo program where they will let you try various props before buying one. You might want to contact your local Merc. dealer for info.<br /><br />Good luck.<br /><br />Brian

 

[roy w. shakun]

Re: What prop size for Yamaha 150 on Wahoo 21 CC?

You can have the prop cupped by 3 degrees, if it is not already and that would drop your rpm's by 300 or so.<br /><br />That's if it's not cupped.

 

[mhadden]

Re: What prop size for Yamaha 150 on Wahoo 21 CC?

OK, here are the first test results:<br />I went with a 14-1/2" X 17 pitch new Yamaha prop. The boat comes out of the hole great, but WOT only gets 4600 RPM with a light load (1/4 gas tank and 2 small adults). <br />So, do I go to a smaller prop with the same pitch to get the RPMs up, say a 13-3/4" X 17 pitch?<br />Thanks in advance for your help!