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  1. #1

    Join Date
    Oct 2009
    sydney australia

    gp1300r flat spot

    hi ppl im new to the site and hoping someone can help i love the site and love my skis anyway i just bought my second gp1300r 05 model with 48 hours, it has a d plate installed and a prop think its a 14/20 the prob is when im at 4000rpm and 30-40ks just crusing and hit the gas hard it just dies for a second then comes on hard big flat spot it also does it from idle as well but not as bad what you guys think got me f$%#@

  2. #2
    Moderator RX951's Avatar
    Join Date
    Apr 2005
    League City, Texas
    welcome to the forum. Our EFI gurus should chime in shortly to help you out.

  3. #3
    From what I've read on the stock injection is that its setup lean in the midrange. Its probably taking a second to get enough fuel once you snap open the throttle. That combined with your impeller may be your problem

  4. #4
    MX5 is dead on..... If you have a stock 1300 with a 14-20 you have too much impeller and its loading the motor too hard, making it hard for the engine to come up on rpms.
    Combined with the fact these engines are lean in the mid is another factor in your bog..
    You dont need a 14-20 untill you add some power... Milled head, keyway, my throttle bodies, etc..
    Make the horsepower first, then match it with the correct pitch impeller.
    Stock engine requires stock impeller.

  5. #5

    Join Date
    Oct 2009
    sydney australia

    flat spot

    ok so i should take out the upgraded impella and put it back to standard and should b all good
    should i up grade the grate and have a standard impella will this give me a little more top end
    the ski seems to porpous alot will a grate fix this
    sorry for all the questions just want it to run like my standard 07 gp did loved it in the surf

  6. #6
    Re-Read my last sentence in previous post..

  7. #7

    Join Date
    Oct 2009
    sydney australia
    i just rang the mechanic that worked on my ski for the previous owner he tells me that my ski does not have a prop installed it was his other one the guy i bought it from had 2 gp1300rs sitting there my one is standard only mod is d plate so what could make the flat spot
    please help only had it for 3 days now just want it to run how its ment to

  8. #8
    Mongoose's Avatar
    Join Date
    Aug 2005
    Stick an efi controller on the the stumble will go away-Ive had the same issues with 2 skis-a powervalved 04 and an 05. I doubted it would work when it was suggested, as, same as you I had done no engine mods-but it made a huge difference.
    If you need any more efi info-do a search-theres loads of info on here.

  9. #9
    Mike xsockguyx's Avatar
    Join Date
    Sep 2007
    When my ski just had a d-plate i did get a mid range bog. I got an EFI controller and it fixed the issue.

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