Can I get more speed out of this little rubber band motor?

[njmccorkle]

A little different propping question for all you guys used to dealing with the 900hp motors on 75' triple-deep V quad hulls :D

I have a 14' V-hull jon with an early 80s Mariner 15hp that I use for putting around the little lakes and the river here. Dinged (and mostly repaired) the prop earlier this season, but figure I should replace it and use the damaged one as a spare.

I'm getting 17.4 mph at 4800 rpm out of this thing on a glass lake with a 9.25x10P prop. The WOT range is 4500-5500. I've already adjusted the motor height and tilt to get the best speed I can.

Any ideas on props that could push this motor farther up into the WOT rpm range and get me a little more speed? I would think this thing should be able to hit at least 20mph (possibly a couple mph more?) with a better prop.

[Shellback]

Can't help you on a pitch selection, but you should check out Piranha composite props. They have a hub kit, and you can change out the blades. I know they used to let you exchange the blades if they weren't the right pitch as long as they were in new condition.

[yarcraft91]

A lower pitch prop will increase your WOT rpm. You can get props from Mercury all the way down to 5.5 pitch. Most likely, however, a lower pitch prop will raise your WOT rpm, but your speed may improve much, if at all.

If the prop is a bit eaten up, a new one the same pitch will push the boat a bit faster and maybe give you more WOT rpm.

You say you've already optimized motor height and trim. About all that's left is weight distribution in the boat, like moving the fuel tank to the bow.

Of course, we're assuming the motor itself is tuned up to top performance- right?

[Runaway]

turningpointpropellers.com recommends a 9x9p or a 9x10p. Check out there prop wizard. I have used it in the past and is pretty accurate. They have a return policy if it doesn't fit your needs and its not dinged up.