Quote:
Originally Posted by CHANCE1234
So I tried a few props today on not 20SF with a 2001 yamaha 115. The one I've been using is a 13 1/4 X 15 quicksilver aluminum. That got 5800 WOT and 34.9 knots. Then I tried a 13 1/4 X 17 yamaha semi clever and achieved the same exact numbers. 35 knots is just a hair over 40 mph but I figured I'd get a little better top end out of the yamaha prop. Any suggestions?
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That's pretty good Chance. You sound pretty dialed-in. like the others said in your engine height thread, the anti-vent plate might be running a bit low. Is that pic in other thread of the Yamaha prop? Are you sure the Quicksilver isn't 13-3/4 x 15?. Where you able to measure fuel burn? and did you measure speeds at specific rpms? And were you able to determine minimum sustained planing speed w/ either prop?
My guess is the hole-shot was better with the Quicksilver, and that you held a lower planing speed with the Quicksilver. Is that a 2-S or 4-S yammy?
The other thought - make sure you're testing with a maximum load. Like Fr. Frank suggests, make sure your able to achieve your top targeted RPM at WOT w/as full a load as you'll carry. Keep us posted. Thats a very common configuration and the question pops up often.