Change my prop for more speed?

[LHUDSON]

I am thinking about changing props from a 14Dx17pitch to a 14Dx19pitch.How much more MPH will I gain?I have a 19ft Bayliner Capri Cuddy 4 cylinder Volvo penta AQ125 with a 270 outdrive.I think it is 115 horse power.Right now I am at 25 MPH at 4600 RPM.

 

[reddogg]

Re: Change my prop for more speed?

Dunno about how much speed you'll pick up, but a change in pitch is worth about 200rpm.

red

 

[steelespike]

Re: Change my prop for more speed?

Its difficult to predict speed changes; mostly because of the shapeand weight of various hulls.
I couldn't find an AQ125 but based on other models it is likely 125 hp not a lot for as 19 footer.
I believe the AQ125 probably is rated at about 5,100 rpm max wot.
If 4500 is your wot(wide open throttle) rpm your obviously about 600 rpm low.not good for motor health or performance.If you go to a 19" pitch you will probably lower the wot rpm by
another 300 to 400 .
I think you may have performance issues.Is the motor in excellent tune,good compression,
timing set right and advancing as it should.Does the carb open all the way.Is the bottom clean and smooth.
I don't have any experience with with Volvos but the 17" prop seems reasonable and I think the boat should do about 30-35 mph as setup.

 

[Bondo]

Re: Change my prop for more speed?

I am thinking about changing props from a 14Dx17pitch to a 14Dx19pitch.How much more MPH will I gain?I have a 19ft Bayliner Capri Cuddy 4 cylinder Volvo penta AQ125 with a 270 outdrive.I think it is 115 horse power.Right now I am at 25 MPH at 4600 RPM.

Ayuh,... It'll probably go slower, as you've already run outa Horsepower...