Results 1 to 8 of 8
  1. #1

    GP760 newbie on maiden voyage.....porpoises.

    OK - first trip on a jetski....Im hooked....
    Bought this ski from original owner with 180 hours on it.
    It runs GREAT.....I converted to premix thanks to this site.....runs clean.....and fast.

    But it porpoises.
    Now I would think that the guy before me worked out the porpoising within his 180 hours.
    Im heavy (230). He isnt (180).
    Could it be that Im bigger (or maybe that I sit differently) and the ski needs a tweak? ?

    Should I start with Ride plate or Sponsons?
    Id hate to screw up a good setup.

    It also pulls to the left on acceleration...is that normal?


  2. #2
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    Check to see if the plastic trim tabs on the bottom/back of the ski are still there/ in good shape. they tend sag and/or break off. when that happens the ski can pull one way. and it might also give you other handling problems like porpoising. The solution is to find a set of aluminum trim tabs to bolt on there. Other then that, ride plate angle and design can help you tune out the porpoising problem. Also a scoop style intake grate helps suck you down to the water.

  3. #3
    Thanks Cutlass....Ill leave the sponsons and start with adjusting the ride plate. Ive seen a few posts in "search" on what works.....wide range of ideas.
    As far as the trim tabs......theres nothing there on either side......they werent bolted on?

  4. #4
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    I guess it depends on what year your ski is. For some reason I thought it was a 97...which had the trim tab issue. Oh and I think some early 98's as well.
    I've heard putting the sponsons all the way down helps a tiny bit if you wanna try that as well.
    Shimming the rear bolt mounting spots helps with porpoising but scrubs off top end mph...which alot of people hate. But if it makes the ski more fun/easy to ride, then go for it.

  5. #5
    Yeah - its a 97....

    I went back out to see if I was just not seeing them.....nothing there.
    The tail of the hull...each back corner...there are indentations in the shape of the aluminum trim tabs Ive seen in other posts....but nothing there....no mounting holes etc.

    Thanks for the help...might get to it this weekend....more to come.

  6. #6
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    Well maybe its only on the GP1200s. I could have swore I've seen them on GP760s also.

  7. #7
    Just to finish this thread out.....stainless fender washers under the ride plate fixed it (two in the front and three in the back).

    I also found the sponsons to be all screwed up.....the left one was all the way up. The right one all the way down.....hence the pulling to the left.

    I bought this from the original owner......why would they have put up with all that for 10 plus years?
    Would having a sponson all the way up help with 360's?
    I got pretty good doing them even with both sponsons down......

    Thanks Cutlass!

  8. #8
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    Thanks for the update!! Its always good to hear back from people. Yes, sponsons up should help the ski slide around more.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Maiden Voyage SLT 785.
    By beerdart in forum Polaris PWC Performance
    Replies: 29
    Last Post: 07-05-2007, 11:05 PM
  2. BULLRAIDER, whats the word on the maiden voyage?
    By 97GPSLEEPER in forum Yamaha Old School Skis
    Replies: 16
    Last Post: 06-03-2007, 02:13 PM
  3. Maiden Voyage ! I love this ski !
    By MrSxy4Ever in forum Kawasaki PWC Performance (4-stroke)
    Replies: 13
    Last Post: 04-23-2007, 01:13 PM
  4. Project 15F Maiden Voyage
    By 785xp in forum Kawasaki PWC Performance (4-stroke)
    Replies: 0
    Last Post: 04-21-2007, 03:56 PM
  5. I took the maiden voyage on the Green Hulk
    By Green Hulk in forum 4-Tec Performance
    Replies: 48
    Last Post: 05-16-2006, 08:59 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •