Got my best speed yet but also have issues

[Alex_GPR]

I ran 70.1 today superman in 6" chop thanks to a tip from fernando and a tip from richard(WFO).
My issues are that my RPM's were 7360 and i couldn't get the ski to stop bouncing. My two questions are;
What do i need to do to bring my rpm's down, a 14/20?
Are a set of R&D trim tabs goin to solve the bouncing issue?

[spud]

If your sponsons are like the older GPR's step them first. A 14/20 Dynafly would be a good starting point for an impeller. You can get it pitched from there.

Get the R&D trim tabs later if you need them. When you decide to go all out get ahold of Fercho for the package and Carl at Island for the parts.

[Alex_GPR]

sorry, forgot to post this, he are all of my mods.

Freeflow
PPK
Riva Rideplate
Riva Intake Grate
Stock Sponsons Stepped
Tach
Power Filter
Holes in hood and bucket

I have also spoken to fernando about the package. I plan to buy the package just after the new year. It is on of my winter projects.

[WFO]

congrats Alex...I cant believe it is porposing with the sponsons stepped!

Looks like it time for some trim tabs, you will need them if you go with the package.

What were the temps when you turned 7360?

[Hydrotoys]

I'd look at your setup a little closer. Is your trim nozzle parallel to the 5deg nozzle while at neutral? Any parts hanging down underneath? Straightedge that rideplate yet?

Also, if you were riding in rough water, and are coming from a three seater background, the gpr will be bouncy...until you come up with a package.

[fullboogie]

Forget the trim tabs - use your stockers.

Step your stock sponsons, and check the angle of your steering nozzle in the neutral position using the depth finder on a caliper. May need to also put a thin shim at the rear mounting points of your ride plate if none of the other stuff works.

[RX951]

Forget the trim tabs - use your stockers.

Ditto.

[WFO]

they are plastic on 1300 boats

[WFO]

try a thinner washer in the front of the ride plate first

[Alex_GPR]

What were the temps when you turned 7360?

Not exactly sure... I believe it was between 77-79.

I'd look at your setup a little closer. Is your trim nozzle parallel to the 5deg nozzle while at neutral? Any parts hanging down underneath? Straightedge that rideplate yet?

Also, if you were riding in rough water, and are coming from a three seater background, the gpr will be bouncy...until you come up with a package.

The rideplate does have dip in the center. Forgot to mention the rideplate is also sanded smooth.

Forget the trim tabs - use your stockers.

Step your stock sponsons, and check the angle of your steering nozzle in the neutral position using the depth finder on a caliper. May need to also put a thin shim at the rear mounting points of your ride plate if none of the other stuff works.

What kind of caliper and where can i get it? I just recently moved out so i don't have access to many tools.


Is the 14/20 the way to go to bring the rpm's down? Is it safe to keep running it with the rpm's that high or should i garage it until i resolve that issue. Also, i noticed when i was flushing the ski that the pisser on the right side did not have any water flowing out of it. It was flowing just fine when i was riding though. What do you guys think?

[Alex_GPR]

Oh, just to clarify. When i said i was in superman, i was laying flat as a board on the seat with my feet haning off the ski. That was the only time it porpoised. When i was sitting on the seat crouched down it did not porpoise. It was just faster the other way.


I'm starting to question the rpm readings...my tach just stopped working. It is still lit up like it should be, but i can't go through the diffent menus. It's a tiny tach commercial and i JUST installed it. Maybe a wire came loose??? I didn't have time to check everything out. What kind of rpms think would be normal for my setup? I know every ski is different, i'm just looking for a ballpark figure. 7360 just seems way too high for me.

[Alex_GPR]

Anyone have any ideas why the pisser on the right side isn't flowing any water while flushing? It was flowing just fine wheni was riding.

[ABBOTT]

Anyone have any ideas why the pisser on the right side isn't flowing any water while flushing? It was flowing just fine wheni was riding.

Mine doesn't either - sometimes there is not enough water pressure from the hose to reach the second half of the pipe where the right side exit comes from. It's ok as long as you see it coming out while riding in the water.

[fullboogie]

Alex, you can pick up a 6" digital caliper online from harborfreight.com. Or, you can get a manual one from Autozone, etc. They're invaluable when working on our skis.

[ramnj]

Anyone have any ideas why the pisser on the right side isn't flowing any water while flushing? It was flowing just fine wheni was riding.

Open up the water pressure and it will flow out of both. When flushing half the water goes to the engine while the other half gets dumped out, at least that's the way it is on the 2000 GPR.