Prop Question

[cbd15178]

2011 Nitro Z9 250PRO XS, not sure of the PTP measurement at this moment. I am currently running a Fury 3 25 which is what came on the boat when I bought it. In the hotter months I was getting around 68 WOT by myself and tournament load at 6200 RPM. Now that the water is cooled, I am running 70 WOT by myself, loaded and wells full. I feel like I should be getting a couple more MPH's out of this setup. Would I be better off going up a pitch and swapping to a Tempest?

[21XDC]

Running light, You might try a 26 Fury3... With a load, You might try a 26P Tempest plus.

[lpugh]

If tach and speed are accurate numbers, you have 21 percent prop slip. Try dropping the motor a 1/2 inch and report the numbers
Do you have poles on that boat
I would expect somewhere around 5750 at about 72-74 with that combo set up right without poles

[cbd15178]

No, there are no poles on the boat. Tank is only half full of gas also.

[cbd15178]

My PTP measurement is 4.125”. I ran the boat today and got 71.5 @ 6200. I’m getting more speed because of colder air and water temps I know. This seems higher on the RPMs than I would like to be running. Do you still suggest going to a 25P and dropping the JP 1/2”?

[lpugh]

Is that rpm taken from a smarcraft. or digital tach or analog? that would still represent about 16 % which way to high, I would stil drop it a half inch just to see if it take care of the the high slip numbers
Are you sure you have properly measured the prop to pad?
Use a level on the floor, adjust tongue height to set the pad of the boat to the same angle as the floor, then level the cav plate with the trim to set it to the same angle, measure from the floor to the pad and measure from the floor to the center of the prop shaft and calculate the difference
4 inches would be to deep compared to any other that I have dealt with, But that rig should not be able to pull 6000 with a 25 Fury

[cbd15178]

RPM is from the analog gauge.

Yes, the measurement is correct. I checked it twice to confirm because I knew 4”+ was a lot. Pad was level, cav plate was level and I just went to confirm that my garage floor was level.

[lpugh]

Get that tach checked, I believe you will find it is way off. I would recomend smartcraft or vessel view link which is about 250.00 I think, and use a phone app for dead on acuracy