Yamaha GP760 Porpoising

[nrladeere]

I just got a 760 Waverunner. It has the power trim system as well as the adjustable sponsons on the rear. It tends to want to porpoise a lot when going over wake. Are there trim tabs or other mods which will reduce this some. The trim will not stop it.

 

[paulgp6022]

Re: Yamaha GP760 Porpoising

The trim isn't power, it's manual. The porpoising is caused by the hull, it is a design flaw. I used to own a 1999 Gp760, it porpoised so bad I sold it, only after sinking hundreds of $$ into ride plates, sponsons, trim tabs, intake grates, etc. Nothing worked. Do yourself (and your wallet) a favor and sell that ski and buy something else. Good luck

 

[DJ]

Re: Yamaha GP760 Porpoising

Agree with SS Minnow, our family's GP 800 (I think it's a 800?) does the same thing. You have to ride way forward on it to keep the nose down.<br /><br />The manual trim is useless.

 

[paulgp6022]

Re: Yamaha GP760 Porpoising

Yes, Yamaha makes the GP800 and Gp1200 as well. The GP760 was discontinued and replaced with the XL700 3 seater. The GP800 and Gp1200 have the same hull as the GP760. It wasn't until 2000, when the Gp1200R came out, did Yamaha change their hulls.

 

[BiXLL]

Re: Yamaha GP760 Porpoising

Pull your ride plate off. Install 2 washers between the hull and the plate in front, 1 washer between the plate and hull in rear. Did WONDERS for me! (thats 2 washers on each bolt in front, 1 on each in back)

 

[shocked99@hotmail.com]

Re: Yamaha GP760 Porpoising

I have the same problem with my Kaw900ZXi.<br /><br />When I go to replace this thing, what do I look for in hull design to know I'm not gonna run into the same problem again?<br /><br />Eric

 

[nrladeere]

Re: Yamaha GP760 Porpoising

I installed a Riva Rideplate. Put 2 washers on the rear. Rides like a dream, no more porpoising! The extra few inces on the rideplate makes all the difference.

 

[BiXLL]

Re: Yamaha GP760 Porpoising

nrladeere <br />Try the washer thing I posted. Fercho, Razbo56, and myself came up with this after much testing!

 

[DJ]

Re: Yamaha GP760 Porpoising

Just wanted to let everyone know that BixLL's "fix" worked very well.

 

[Jeff Walkowiak]

Re: Yamaha GP760 Porpoising

See if there is a little more adjustment to put the nozzle down on your cable from your trim, At the threaded end where it attaches to your nozzle the further down the less the nose will rise, adjusting the ride plate is also a way to help and if you want to check out my steering systems for jet skis it also reduces hop and stabilizes the hull at high speed plus the patented design gets you on a plane faster

 

[ozdano69]

Re: Yamaha GP760 Porpoising

i also have a 760, 1997. what kind of washers are we talking about? do i need metric/us tools to remove ride plate? <br /> what is the rideplate? thanks, dano (a newbie)

 

[gflat65]

I know I'm digging up some history here (last post on this was 2004), but I am trying to get a 2000 gp760 ready for family week at the lake (jet ski is new to me, and I'm relatively new to jet skis). I replaced the broken sponsons, hoping that would help a little on the porpoising, but no luck.

Above, the mention of adding washers under the ride plate as a fix is my next attempt. My question is whether the double washers should go under the front or back of the ride plate. It seems like if I wanted the bow down, I'd put double washers under the rear of the ride plate. Does that make sense?

Are there other options that have come up over the last 13 years that help with the porpoising issues?

TIA

 

[dannyual767]

gflat, if I were you, I'd do what they say to do and put the double washers in the front of the plate. Give it a try and let us know how it works out. Good luck!

 

[GA_Boater]

I know I'm digging up some history here (last post on this was 2004)

gflat65 Start a new thread. 2004 is ancient history.

Closed.