prop sizing/jack plate

[fish4life]

My setup is a 18'10 challenger 395 se radical one pro bass with a 1996 prov150 with a 23 pitch prop,3 Blade,with a six inch jack plate,havent ever touched the jack plate.The boat gets on plane faster than any other boat ive been on.But it only hits about with 5000rpm with the trim at about 3,when i trim it up,the rpms raise slightly but not to 5500, it starts getting squirrely for some reason at about 5100 or so.im confused because the thing gets on plane very fast but only hits around 5000rpm before it gets scary.Im thinking the jack plate needs be lifted higher or something.

Thanks,
Josh

 

[stratos21xl]

what kind of prop is it and how far below the pad is the prop shaft? You may have the motor set to deep on the jackplate which will give you good hole shot or take off and lower RPM's on top. What kind of water pressure do you have at wide open throttle? As a rule of thumb you will gain RPM's when you raise the motor height on the jackplate and it will probably help the getting squirrelly but you might lose take off or hole shot.

 

[fish4life]

Its just a oem?im guessing theres no markings on it other than 23.And im not sure of the rpms.i know the water pressure is good at wot.i can raise the jackplate higher i have a feeling.the hole shot is ridiculous,so i dont care to lose some.and idk what the length with the pad of the prop shaft?idk anything about that.ill just have to raise the motor up a little bit higher on the jackplate.and whats the best water pressure to have,before u need to lower the trim or motor down?whats the pressure needed in other words to not burn out the motor or anything.

 

[stratos21xl]

you need to keep between 15 and 20 psi of water pressure at wide open throttle on the motor. Before you raise the motor on the plate I would record your current setup as in water pressure, rpm's, and speed at wide open throttle. Get the boat up to about 3/4 throttle and start bumping the trim button a little at a time, the nose of the boat should lift and rpm's should start to climb. Continue doing that and increasing throttle until the boat stops lifting. Most of the time that will be level or just past level depending on if you have a jackplate and how much setback you have on the jackplate 6, 8, or 10 inches. After you figure all that out go back and raise it one notch on the jackplate and run it again. Record your water pressure, rpm's, and speed at wide open throttle and keep going to you lose speed or water pressure. Once you start losing speed and or water pressure then drop it back down one notch on the jackplate and you should be dialed in. You can also record your hole shot by timing how long it takes for the boat to get on plane with each adjustment to the jackplate.

On another note I would get a Sharpie or find a way to mark where the motor currently is on the jackplate just in case you have to go back to the normal set up. There is no one setting fits all as every hull, motor, and prop like different set ups. It's usually just trial and error.

 

[fish4life]

Thanx.