232 with twin F150 prop size?

sandkin

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My 2006 232 Gulfstream ,with a painted bottom,has 13 3/4 x17 Black painted SS props on twin F150 Yamahas.
I could only get 5400 RPM @ WOT
This was with a light load 1/8 fuel ,No water,and three people onboard.

I have since moved this boat from Florida (salt water) to Canada (fresh water)

Will the change in elevation and from salt water to fresh water make any difference?

Also ,what size and make of props are other 232 owners using?
 

ocnslr

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That is far too low an RPM for WOT with a light load.

Is the bottom clean? I can lose several hundred RPM with just a little barnacle build-up.

Did you have the engines trimmed up until just before the props start ventilating? RPMs wil be much lower if you have the engines trimmed down too far.

Higher elevation means less dense air, which usually means a loss of power. Same effect as the difference between hot summer air and colder winter air, so perhaps the lower temperatures in Canada will offset the higher elevation. :D

As to the fresh vs salt water, I have no personal experience but the boat will float just a bit lower in the water in fresh water, so you will have more wetted surface and that means more drag and less speed..

Good luck.

Brian
 

duconce

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The f150 yamaha I had on another boat came with a 14 1/4x 17 SS prop, I would, as pointed out, think that trim or elevation or both might be the problem.
 

grady23

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Come on Guys -- F150 is a computer controlled engine. The altitude should have absolutely NO affect on performance -- The system will compensate for air density changes. There must be a different problem. As far as I know, this is the stock prop for a 150. How old is the fuel?? Maybe it's heavy water? LOL
If the prop size was wrong, it would mean the props are too high a pitch and need down-sizing. I don't think the boat will perform well at all with a smaller prop pitch.
 

sandkin

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I know this is very late reply, but my problem turned out to be old fuel. Once I fueled up with new fuel that I had added Ring free and Stable Marine fuel stabilizer to, all is good. WOT is 5900 RPM at 41 MPH full of fuel and water, with 4 adults.
Thanks everyone for their thoughts.