prop

wildeyes

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I put a 90 hp on my boat with a stainless prop. when I trim up it stops at 5100rpm I can't trim up anymore question I have is, does this happen because of the prop degrees or does the motor have to be adjusted down or up more. My last motor I could trim up to the point it would come out and over tac. I can go 38 to 40mph down stream and 35 to 36 up. max rpm is 5500rpm I would like to get it closer to 5300 to 5400 rpm.
I hope you understand what I'm saying.
 


Wild and Free

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Too low rpm is too large diameter not too much pitch for starters, need to drop about 1/2 inch diameter for starters and go from there. Go to the engine MFg site they all usually have recommended prop sizes for each engine on different types of boats as a starting point.
 

wildeyes

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checked the mfg site and they call for a 13 X17stainless. On the boat now is a 13.25 X15 no wonder it stop trimming at 5100 rpm. Now comes the fun part finding a prop that I can try before I buy. I checked with rivercity and they don't let you try before you buy. valley acted like it was a problem just to talk about it. Anybody have any ideas ?
 
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watson

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Brainerd props in Brainerd mn or kovash marine in moorhead mn will both let you try out props before buying.
 


Wild and Free

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Not sure if the Toy Box in Mandan carries props or not but they are good guys, Moritz, Bismarck prop works or there is a guy that usually has a ton of props for sale in the finder every week.
 

Traxion

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I would not go up to the 17 pitch even if you go down to a 13" dia. prop. 1" of pitch change usually equals 150 RPM loss or gain. Losing diameter but adding pitch will work against each other. If you can find a 13" x 15p I am guessing that will be the closest.
 

Captain Ahab

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Sounds like your motor could move up a couple holes if you can't blow out your prop. I would start on the highest hole and work down if it is too loose.
 

wildeyes

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I took off the prop on it now it is 13.25 by 15. I call bis prop. and talked to him about props after talking to him I'm thinking the same thing you are Boss I think the motor is to low.
 


eyexer

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pitch effects rpm the most. diameter affects it also but not nearly as much as pitch. and with props the size your looking for there is very little variation in diameter between props. not nearly as much as with large hub props.
 

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