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  1. #1
    thetolleyman's Avatar
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    GTX RFI new motor issues, Any help would be great

    Dropped a new engine in a 98' GTX RFI this week. I've done a couple of these before and many carb'd models. This is the first time I've had this issue:

    1. A bit harder than usual to start, just have to give it a little throttle.
    2. Idles poorly below 1800 rpm.
    3. Revs slowly, takes 2-3 times as long as usual to get up to 6000 rpms.
    4. Takes a while to return to idle after revving too.
    5. Sometimes after revving it holds at around 4000 rpm to a few seconds, sometimes longer.
    6. Backfired a few times (I never had a Seadoo backfire on me until now).

    What I've done:

    1. Checked wiring harness and connectors to make sure I haven't put something in the wrong place.
    2. Removed intake and reset valve timing, it was fine anyway.
    3. Drained old fuel and added new.
    4. Checked oil pump setting, its right on the mark.
    5. Checked plug gap and spark.
    6. Checked compression, its not as high as I'd like to see on a brand new motor but its over 120 psi.


    How should I proceed, should I just go ahead with break in procedure and see what happens. I know the ignition timing can cause these symptoms but I can't see how that would be off as the keyway dictates where the flywheel goes and there's a pin on the magnet cup too so I can't have put those on wrong could I? I've never had to test fuel pressure or injectors before. Is there a good way to clean injectors? I guess I'll pull the fuel filter today and take a look there. I should add that the ski ran fine prior to a crank bearing wearing out so I would suspect the electronics and such are fine.

    This is a SBT motor. Not my choice, owner brought me the ski and the motor to install.


  2. #2

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    TPS been reset?? Needs to be done using BUDS I think.

  3. #3
    thetolleyman's Avatar
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    Hmm, never heard of that.

  4. #4
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    plus one on the tps..big trouble maker. You can do it with the seadoo purple handheld or candoo...don.t know about the others. Buds is great..if you have it.

    check injector wiring and be sure the gas is fresh.

  5. #5
    Where or who did you get your engine from if you dont mind me asking. I will be needing to have 2 787 RFI's rebuilt. Thank you

  6. #6
    Sorry, just saw you said SBT. I was considering using SES and have them use Pro X pistons, and instruct them not to cut the head to reduce compression..

  7. #7
    thetolleyman's Avatar
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    I'd stay away from SBT. I've installed three for customers of mine, and two of the three have had issues. A few more hundred dollars is nothing to avoid the extra headaches. Just my opinion, others I'm sure have had good luck with SBT.

    Personally I'd just build them yourself if you have the mechanical abilities. You'll feel good about it when your done.

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