Go up in pitch?

[Black Max]

Boat: 16ft Hydra-sports Z-260
Motor: Johnson 115 JPLEEM V4 Eagle 60*
Gear Ratio: I believe 2.0
Prop: 20 Pitch Raker
Speed: 54.5mph GPS and speedo.
Setup: 6-inch plate, shaft 4in. below transom
Slip: apparently .015 according to calculator, not sure if its possible
RPM: Has to be near 5800 at that speed and slip/ stupid tack just bit the dust. Slip and rpm may be higher. (New System-Check tach is a doozey for us poor college kids, I've been counting my pennies for it).

Is the speed and efficiency good for this set-up and horsepower? Holeshot is good.

I believe the recommended rpm is 5400, but just had to push it with the GPS in hand. d

If the numbers are right what should I do to bring the RPMs into the correct range and not lose any speed? Higher pitch prop?

 

[Ron G]

Re: Go up in pitch?

i think your about right..i dont know about the slip but i think your in the ballpark,sounds like the raker is hooking up good the way ya got it......is 5800rpm at wot or do have more?

 

[Black Max]

Re: Go up in pitch?

5800 is about wide open, but max speed is probably around 5500. The prop runs the best when it is cavitating a little. Sounds good then, but I need to get the chipped blade edges fixed and the blade tips staightened a little bit. Some say bluprinting can add 2 to 3mph, not sure if its true.

 

[Ron G]

Re: Go up in pitch?

Its a possibility but thats alot of money to speand and like i was told about it if your not running in the 70mph or higher ranger you probably want be able to tell.
Is it cavating at the top of your trim?and does your rpms move up any?hows your water preassure at that point?
And also we need that tac fixed to know exactly whats happening.

 

[Black Max]

Re: Go up in pitch?

Yes, it is cavitating at the top of my trim, and the rpms do move up. This is even worse when turning. Water pressure isn't a problem, around 28psi. Ditto on the tac problem, replacement coming soon. The speed is fine with me, but the cavitation is pretty bad and would be nice if I didn't have to cut way off the throttle when making turns. Do 4 blades hold better?

 

[walleyehed]

Re: Go up in pitch?

It's normal to have venting occure in turns with a proper set-up....expect to trim in some during turning.
5800+ for the looper..nothing less with a normal load.

 

[Ron G]

Re: Go up in pitch?

Like Kenny said you have to expect to trim in,im so used to trimming in thats like shift gears in a truck.and if setup right the 4 blade would be the same.