Prop Advise Needed

[fishinalot]

Hello

Here is my problem. I have a F50 Yamaha Tiller on a Alumacraft Classic 165 that came with a 10 5/8 x 12 pitch prop. I get 28 MPH, 5500 RPM at top end and the troll speed in Reverse with the adjustable RPM's down as low as it can get is only 1.30 MPH in reverse.

I talked to 3 different mechanics before I purchaced a 11 5/8 x 11 pitch prop and they said I would get more RPM's and the troll down speed would be slower.

It now trolls faster in reverse! ( 1.40), my top end is now 27 MPH and the RPM's dropped to 5400!

The manufacture states the RPM's should be around 5800. I could trim it up to get that.

My question is this.... What prop should I get to get my backtrolling slower and my RPM's on my top end higher?

( I do have trolling motors to use and that is an option,also wind socks), but I would like to also have the right prop on the unit to get the best out of the F50.

Thanks

[Sonicrunch]

pitch isn't everything. the new prop may have a different rake, different cup, etc.

[marine_man]

The manufacture states the RPM's should be around 5800. I could trim it up to get that.

One clarifying question here... when you get your max RPM's your running at Wide Open Throttle, with the motor trimmed out to the optimum running position, right?

One other thing here... while you did back off on pitch, you increased diameter which still amounts to pushing more water than before, albeit not as effectively as a increase in push.

marine_man

[fishinalot]

My RPM's @ 5500 is with the Motor Trimmed all the way down not out. I can get up to 6000 with it trimmed out.

The reason I had to go with the 11 5/8 x 11 pitch was because Yamaha does not have a 10 5/8 x 11 pitch prop for the F50.

I did call Yamaha today and they said I should stay with the 10 5/8 x 12, live with it and throw out the wind sock.... May throw out the yamaha and get a Evinrude E-Tec!

[hydro]

Your diameter change netted a 20% increase in the area of water the prop is working. That's where the change came from.

I would agree that your original prop is better in your application. Look outside of Yamaha for other prop choices, just be sure it is hubbed for your motor. Maybe contact Soderblooms for a recommendation.

[Northlander]

Look up Jay Soderbloom and he can give you the compltet run down. He knows his props. Just do a search for Soderbloom.