Need help

Did you look down the throat of the carb to see if the throttle plate was perfectly vertical while the shifter was in the wide open position?

 

Not really. Need to change the pitch on the prop. Basically in auto term that is your final gear ratio, your running to big of a prop to get the top rpm.
If you read up on it you will see what different pitches will do for hole shot and wide open speed.

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200 rpms per degree of pitch.
I would probably try a 17 pitch first.
The lower pitch number will also decrease speed at times, but increase hole shot.
Alot of the boats went larger pitch trying to get a little speed
Se a 15 pitch moves 15 inches per turn
While a 21 moves 21 inches. That does not include slippage that all have.
You may be able to find a marina near you that will loan out a prop.
In addition stainless steel will have better performance than aluminum.

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Should get you near top rpms.

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I would make sure you address this issue as it will cause a RICH condition during motor operation!

 

With limited information i would not assume prop is the problem.I would contact Crestliner and find out what prop came on boat when shipped,build sheet should be on record.If it is original prop(pitch/dia) only then can you know if engine or hull weight is the problem.A good engine diagnosis could tell you of other issues with the engine its self.Might take the guess work out of solving your problem..

 

Agree with textox. Too many questions about fuel, spark and air before trying another prop. Questions remain unanswered about the prop also, such as did the boat ever perform acceptably in the current owner’s possession.

 

Yes Kroppe,Too many systems come into play there,timing,compression,carb tune ,fuel pressure,and the possibility of water in the fuel or a leaking head or more commonly an intake gasket.Lots more to consider than the prop..

 

I have a 1986 Sylvan with 4.3Cobra outdrive, I put a pertronix electronic ignition in it. It worked fine at first, then I took it to the Bay. It wouldn't rev over 3000 rpm's. Found out one of the magnets came off , so it was only hitting on 5 cylinders. Put the points back in it and it redlined. That is a glass 19' boat will do over 45 gps mph.
The magnets are under the distributer cap, a piece of green tape is all that holds them in place,you might want to look there.


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@Smitty03 smitty did you get this sorted?