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SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

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  • SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

    First off, thanks for having a look. This is for a 2001 ZXi 1100 with new hotrods crank and Wiseco top end that I'm converting to CDKII. Proper breakin was performed with CV carbs, which is why I decided I don't like them when compared to my XP.

    I recently purchased a set of SBT rebuild kits to rebuild a set of 1996 ZXi 1100 CDKII carbs with accelerator pump to replace the non-adjustable/tuneable CV carbs on my 2001 ZXi 1100. I went through one carb at a time and rebuilt them, making sure to spray carb cleaner through all the fine passageways and then blow them out with mild compressed air. (have rebuilt the carbs on my Seadoo XP and Seadoo GTi twice, so familiar with the process) I re-used the stock springs, but replaced the needles with the new SBT ones provided. (Looked Viton tipped?) Tested pop off, which was 26-30 on each, although didn't seem a clean "pop" like I get on my XP. I assume a difference in carb design? While I had the carbs off, I also pulled the intake manifold, inspected the reeds (which were mint) and following another post, sanded the insides of the intake manifold to satin metal finish. I also tapped a 2nd brass barb fitting (placed oil soaked rag in intake to catch metal shavings) for 2nd fuel pump on this set of carbs.

    So I get everything back together, with all new intake and carb gaskets from SBT. Highs set to 1 turn out, lows set to 1 1/8 out. Made sure to align throats of carbs to intake to minimize staircase. She fired right up with a little fuel in the throat, but I left the Flame arrestor off so that I could inspect as she was running. Things looked fine, and adjusted the idle up a bit on the trailer with hose, but after a couple short chops of the throttle, noticed the rear carb was dribbling fuel from the high speed circuit at dead idle. The other two were not doing this. If I throttle it up, it seems to go away, but the excessive fuel causes it to idle rough, and I would imagine would cause her to load up over long idles.

    Would this be the needle coming off the seat to soon? (low pop off) Or is this the thin plastic diaphragm provided not seating correctly on the high circuit?


    On a second note, how the h@ll are you supposed to adjust the high and low on this ski without having to pull the carbs every time? Just seems crazy that to simply adjust the screws up or down, you'd have to replace the base gaskets each time you remove the carbs. Is there a crazy long screwdriver tool to reach in behind the carbs to access the plastic adjustment blades?

    Thanks for any assistance you can provide. I am so close, and its frustrating to see this much fuel dribbling off just one of the carbs.

  • #2
    Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

    Okay... UPDATE: so upon pulling them out again, and having found an SBT document outlining the pop off procedure for these carbs (different from SeaDoo - my mistake) I was able to get accurate readings from all needles/seats. There was some variation, but nothing extreme. And none of the needle/seat combos leaked with 20psi sustained. Filling the entire seat area with WD40 got me the "clean" pop of pressure - not just "wetting" the needle. I also went ahead and dialed them all in to 28/29psi after 5 times each, just to be sure they were consistent. I also found another document outlining the proper procedure for setting the needle arm, removing the "play" in the arm to the cross post, and what distance away from the pump body to set. (was recommended by numerous people to use 1mm)

    After getting everything hooked back up and the carbs torqued in, then double checking all connections, I was only able to fire her up for a minute as it was 11pm. But she fired right up with only a split second of full choke, and then sounded way better @ idle. No pinging like before. And it doesn't appear that the PTO carb is dripping like it was, but I won't know for sure until I get more time with her running tomorrow.

    Will keep this post updated for others interested....

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    • #3
      Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

      See how it runs, for adjusting the high and lows easier the trick is to cut small pieces of paper clips and epoxy them as tee handles into the slots on the adjuster screws, make adjusting much easier.
      SBT Tech Support is here to help with your problems.
      We try to answer each question quickly and accurately.
      Please do not use Private Messaging for Tech Support, use the forums.

      Comment


      • #4
        Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

        Originally posted by Technical Support View Post
        ...adjusting the high and lows easier the trick is to cut small pieces of paper clips and epoxy them as tee handles into the slots on the adjuster screws, make adjusting much easier.
        Oh that's awesome! Thank you very much for providing that tip. Seems so freaking obvious now... hahahahaaa ...

        still going to have to hold my 3 yr old son upside down in the engine compartment to reach his tiny arm in behind the carbs to adjust the center one.... I mean... he keeps asking me to help fix them, so.... gotta start his addiction early... LOL

        Comment


        • #5
          Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

          Yes little hands work well, train him when he's young.
          SBT Tech Support is here to help with your problems.
          We try to answer each question quickly and accurately.
          Please do not use Private Messaging for Tech Support, use the forums.

          Comment


          • #6
            Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

            Okay... so I took it out this past weekend, and while she ran pretty good, although I still have tuning to do with the low and high speed screws (starving @ hole punch, reduced top speed) I took the cover off the air box, and it seems that the PTO carb is still dribbling pretty bad at idle from the high speed circuit, causing it to load up and run a bit rough. Clear out when you hit the throttle, but still bothersome....

            As indicated, I went through the carbs again last week and made absolutely sure pop offs were all identical, and made sure the thin plastic check valves were in order (although I did notice some curling to them, but originals had similar) What else might cause this dribbling? One thing to note is that it sounds like there is alot more "suction" on that last carb. Far more prominent sound than the other two. Don't know how this could be possible, as I checked the compression, and it was 130 across all three cylinders, although I have not done a manifold pressure test.

            Any ideas are appreciated. I'd prefer to not have to order an OEM rebuild kit @ $70, but fear I may have to to know if it's the kit. I guess I could put the old carb parts back in, but diaphragms were pickled pretty bad and the plastic was pretty warped from sitting for so long with fuel in them.

            Comment


            • #7
              Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

              If the idle is set too low the engine will shake more causing the fuel to dribble, if the needle and seats are worn then it will dribble too.
              SBT Tech Support is here to help with your problems.
              We try to answer each question quickly and accurately.
              Please do not use Private Messaging for Tech Support, use the forums.

              Comment


              • #8
                Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

                Originally posted by Technical Support View Post
                If the idle is set too low the engine will shake more causing the fuel to dribble, if the needle and seats are worn then it will dribble too.
                The seats were cleaned well with Qtips saturated in carb cleaner, and do not appear to be worn when viewed through a magnifying loop. The needles were replaced with what you provide in your rebuild kits, and appear to be Viton (dark grey) tipped. She idles relatively smooth in the water on the trailer at about 1300-1400rpm, obviously higher out of the water, but I still see this dribble when in the water on the trailer... but the excessive fuel from the dribble causes the idle to roughen and a bit of ping/knock... once cleared out, it smoothes out, but if left for a minute @ idle, it roughens again from the extra fuel.

                Just don't understand if it's vibration, why they all wouldn't act the same... I've seen some posts on other forums where others have experienced this same "dribble", but have not found any where there was solution/fix to it....

                Comment


                • #9
                  Re: SBT rebuild kits for my ZXi 1100 CV to CDKII conversion, excessive fuel @ idle

                  It could be the 1 seat is worn.
                  SBT Tech Support is here to help with your problems.
                  We try to answer each question quickly and accurately.
                  Please do not use Private Messaging for Tech Support, use the forums.

                  Comment

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