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  1. #1

    Join Date
    Mar 2011
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    Tallahassee, Florida
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    98 GSXL Low RPM at WOT...

    I have a 98 GSXL, actually considered a 97.5 with the white 951.

    When running on 75 degree flat water, it will top out at about 6720-6740 rpm.
    I understand it should reach about 7000 rpm, but don't know where to start.


    Bought the ski a few months ago. It has an SBT engine, which has less than 50 hours on it - according to the previous owner.
    Stock pump and ride plate.
    I am running premix and use a 50:1 ratio.

    Any suggestions?
    What to check for?

    I ride with a guy that has an 08 Kawi STX-15F and he pulls away from me, slowly, but pulls away. I think, if the ski will rev out, I should hang or pull from him.....


  2. #2
    RumRunnerRon's Avatar
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    Mar 2010
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    Portland, Oregon
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    I would verify good even compression. Verify your oil ratio is what is recommended for the oil you are using. If I'm not mistaken Seadoo oil is 50:1 and Amsoil Interceptor is 40:1. If you are running to much oil rectify that and change plugs. Make sure you don't have the gray fuel lines. Check the fuel selector valve for corrosion/restriction. Check and clean the internal carb filters. It may be time to do a carb overhaul. If I've left anything out or fed you any bs someone will chime in most likely.

  3. #3

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    Mar 2011
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    I use Quicksilver premium, which meets the spec that SeaDoo requires and run 50:1.

    I replaced all the gray lines and cleaned out the selector at the same time.

    I have not done the carbs, but they seem to work good. I don't know if the previous owner did them, when the engine was replaced.

    I am going to put new plugs in before my next ride.

    I didn't know if there was anything in particular that would normally cause this or if this was normal.
    I did search the forum and found a few others with low RPM, but they changed pump parts. I didn't see any real answers or that any of theirs were fixed.

    Is 6740 RPM low for a na 951 on 75 degree smooth water on an 80 or so degree day?
    I have no idea, so any help is appreciated.

  4. #4
    Quote Originally Posted by JetSkiRider View Post
    \
    I have not done the carbs, but they seem to work good. I don't know if the previous owner did them, when the engine was replaced.
    How are you basing that they "work good" if the ski doesnt turn full RPM? And if you are unaware of the previous owner did them or not what are you waiting for.... Pull them apart and ensure everything is ok ASAP to prevent a lean seisure dude to blocked internal carb screens....

  5. #5
    RumRunnerRon's Avatar
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    Sounds obvious the prev owner didn't do anything to the ski if you found gray lines on it. Gray fuel lines is a well discussed topic on here so not sure why you would only do some of what is required to ensure you don't blow that ski up . Stand corrected on the ratio issue. Looked up Interceptor and it's 50:1 as well not sure what thread or the topic being discussed at the time. Check the impeller pitch as well. Maybe the dude replaced it and it's the pitch that is dragging your rpm's down. I read a thread on here not to long ago that dealt with changing the impeller pitch and how it affects rpm. So that is even a possibility.

  6. #6

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    Mar 2011
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    Tallahassee, Florida
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    Carb rebuild it is....don't want to blow it up!

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