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waverunner xlt800 2002 carburetor tune up or settings

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  • waverunner xlt800 2002 carburetor tune up or settings

    I have 2002 waverunner xlt800
    which was flooded last year. did rebuild carbs and clean engine. make it start. engine running strong and starting right away! even better then it was before. but i have 2-4 miles/h in the water. when i open throttle all the way up it makes noise like its get to much gas.
    impeller in good condition, good compression. Only thing could be it's gas/air mixture. i did tried to change settings, but no luck so far. all manuals which i found so far not really clear for me.

    so thats my question: can anyone help me with short manual how to do it right? not from manufactory or some shop, like sbt. how did you do that?

    how deep should be screwed in needles of high and low speed? how to do this 1 and 1 1/2 turns? is this separate control of high and low speed mixture? because i have 2 screws, one will be for gas second for the air?

    well i need manual how to dial in your carbs after rebuild.

    100% sure it's carbs settings, because everything else already replaced.

    thank you all in advance.
    season start... i want to be in the water

  • #2
    Unless the ski is highly modified, no need to change low and high speed screw settings. There are actually 3 settings in the Mikuni carb, needle and seat, low speed screw and high speed screw. There was never a need to rejet the 800's, they never came with a catalytic converter, and they were plenty rich from the factory. Dona simple search for the settings, I know SBT has the settings on their website under the tech stuff. Set your screws back to stock, and go from there. The lower screw is the low speed screw, the higher screw is obviously the high. Unless you went into the carbs, the N&S, and spring should be correct. Have you ever rebuilt the carbs? If not, they should be rebuilt. Could have water in them that is corroding things. Replace the seat with the same size seat (it does NOT come in the kit) and reuse your spring, to ensure your pop off stays correct. Only use genuine Mikuni kits, you'll need the kits for the I body carbs. Also, check compression to ensure you don't have a cylinder low.


    • #3
      i'm not trying to change it, trying to set it up right. Ski doesn't have any modes. but i did rebuild carburetors and after rebuild notice mixture is too rich. so i was trying to change settings.
      still no luck. found nice video manual - "how to". did everything like they said.
      now i have, easy start, 2-3 cranks and it's running. good take off in the water. but then, max speed no more than 6 m/h. can not tell my rpm or exact speed, because dash cluster broken.
      when i open throttle 100% it makes sound like its on high rpm but no speed... out of water, on the trailer it works just fine.
      not sure what i'm doing wrong now. don't want to go to the shop, to pay 104729388974$ just for simple tune up.
      i don't think it's that simple. anymore.


      • #4
        How do you determine if the mixture is rich? even with a lean mixture, it will not develop speed either. Have you tried pulling the choke throttle and trying to drive?


        • #5
          i took out spark plug and it was wet. and dark black color. from my motorcycle expirience it means mixture is to rich. i did tryied pull up chok and engine died.


          • #6
            Several questions needing answered before we can get to the bottom of this. Forget everything you know about motorcycle carbs. These aren't the same.

            First and most important. What brand rebuild kits did you use to rebuild the carbs and what did your pop off pressure test at before and after rebuilds?

            What are your low and high speed adjusters set to currently? Your low speed adjuster is the lowest on the carb, this controls idle fueling. The high speed adjuster is on the opposite side of the carb and closer to the choke plate. This controls 3/4 to wide open fueling. You are checking how many turns it takes to seat the needles. So when someone says "lows are set to 1 1/2 turns" that means from lightly seated position they turn them 1 1/2 revolutions out.

            The manual for a 2002 XLT 800 states the following.

            Low Speed: Mag Carb - 1 5/8 PTO Carb - 1 3/4
            High Speed: 1/2 for both carbs

            Main Jets 150
            Pilot Jets 90

            Needle Valve Size 1.2

            Not mentioned in the manual but critical is they use 115 gram springs. This results in a very high pop off reading with the 1.2 needle size. This is important to get right and why that is included with the first thing I asked.
            1995 Raider 1100 - Sold after 16 years to a close friends son...gone but not forgotten (Still see it all the time )
            2008 RXPX - Fizzle F1000 w/Relocate Kit, 4" Air, Torque Plate, Free Flow, OPAS Delete, Supertech Retainers & Springs, Solas Impeller, R&D Grate, etc.
            1999 Yamaha LS2000 Jet Boat
            Many skis bought/sold/worked on


            • #7
              i did use some random(generic) carb rebuild kit. no brand. and don't understend the diference. please, if you know explaine me please

              second - presure. did not mesure it, because don't have any tools for that. and dont really want to buy them. but if i have to i will.

              i'm 100% sure i did re-use spring, because rebuid kit did not have it.


              • #8
                i did it!
                with after market re-build kit
                was just carb settings, still slow take off but 40 miles in the water i can do
                it's something. at least i know it's just carburetor settings