rebuilt carb. really messed up

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  • bssford460
    • Mar 2007
    • 10



    #1

    rebuilt carb. really messed up

    my bro removed the carb from out 82 ski nautique and had a guy rebuild it for us, using the rebuild kit from skidim. The guy has built many engines and carbs so i assumed he knew what he was doing. Well his missed something, because now the boat will crank and run perfect above 12-1500 rpm, but WILL NOT IDLE for anything If you try to let it run below 1200 RPM it dies. What i thing are the "booster venturis" seem to be dumping fuel down on top of the butterflies. I took the float bowls off and the float height appears to be right or very close according to some info I got off of the holley website.

    We've moved the idle adjust screws every which way but all the way out and it doesn't matter. (of course, because there is so much raw fuel just being dumped in it.
    So what could the guy that built the carb done/missed that would cause this.
    The choke is operating properly and we checked everything we could find for vacuum leaks.

    We also too the carb off of my brothers supra and the boat cranked, idled, and ran great. There was of course no raw gas visible from the top being dumped down into the carb from the "booster venturis" (if I'm calling the right thing?)

    any ideas or anything i'm not an expert buy any means but this has me baffled. any help is greatly appreciated.
  • adams93
    • May 2008
    • 24



    #2
    RE: rebuilt carb. really messed up

    is it a holley or quadrajet carb

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    • bssford460
      • Mar 2007
      • 10



      #3
      doh, sorry, its a holley

      Comment

      • adams93
        • May 2008
        • 24



        #4
        I think its an idle screw adjustment problem ,on the holly big adjustments are not good ...try to adjust in very small increments ...i would run the idle screw all the way in but be carefull not to over tighten when you seat it you can damage it ...make 1/4 turns out or less equally on each side

        another way to tune it is with a vacume gauge but i dont know how to do that

        Comment

        • JUST-IN-TIME
          • Sep 2007
          • 293

          • ON YOUR BOAT


          #5
          download the PCM manual from here
          it gives u the adjustments

          HUMAN BUILT = HUMAN FIXED

          CERTIFIED MARINE/PWC TECHNICIAN
          switchbait.com

          Comment

          • 81nautique
            • Feb 2006
            • 257

            • Big Rock, Illinois

            • 2012 200 Sport 1956 Correct Craft Collegian Past boats 1955 Correct Craft Hurricane 81 Anniversary Nautique 1960 GlassCraft Ski Nautique #1

            #6
            He's got fuel dumping down the secondaries so it's not the idle circuit.

            For whatever reason the kit from skidim does not come with the correct gasket for the metering plate on the secondary side. It's not a one kit fits all and you need to make sure the numbers on your carb match up to the kit. You probably have a rectangular metering block and the gasket is not correct. This causes fuel to dump down the secondary side continually. Pull the rear bowl, remove the meter block and take a look at the gasket, I think thats your problem. I had the same problem a few years ago with one of their kits.

            Comment

            • Fast351
              • Oct 2006
              • 315

              • Winsted, MN

              • 2001 Ski Nautique

              #7
              The other thing you might want to check is a vacuum leak. Wouldn't result in gas dumping from the secondary boosters at idle (that sounds like a metering block gasket like recommended above). No idle, but runs fine over XXXX RPM is usually a vacuum leak. Just thought I'd throw it out there.
              2001 Ski Nautique / 2007 SV211 TE (gone but not forgotten)

              Comment

              • bssford460
                • Mar 2007
                • 10



                #8
                thanks for the replies guys, we are pretty confident that it is not a vac leak. the deal about the wrong gasket is possible. although i think i held the old and new gasket up to each other and i think they are the exact same, but i could have dreamed that up one night while i was sleeping on what the problem could be? i dunno. we put a carb that my brother had on his truck on there and it is running perfect now. so i dont know. ive' check everthing that i know how to check and i've eliminated vac leak and idle screw adjustment. it is something worse than that. i'll double check the gaskets and see about that. again, thank you for the responses.

                Comment

                • 81nautique
                  • Feb 2006
                  • 257

                  • Big Rock, Illinois

                  • 2012 200 Sport 1956 Correct Craft Collegian Past boats 1955 Correct Craft Hurricane 81 Anniversary Nautique 1960 GlassCraft Ski Nautique #1

                  #9
                  bssford460,

                  Here are a couple pictures of the 2 styles of meter plate gaskets used on a Holley 4160. These are available from Summit if you verify that you have the wrong one in there. I believe you need the style with the squared corners (bottom picture)but your kit probably came with the style with the angles corners and is allowing fuel to slip right past. Pull the bowl and check it out, it's pretty simple and the new carb kit should have come with reusable blue bowl and block gaskets so it should go right back together. Do this soon and get that automotive carb off of there asap.

                  Comment

                  • adams93
                    • May 2008
                    • 24



                    #10
                    If there is fuel dumping in the secondaries constantly i think there would be some debris blocking the float seats from seating....thus dumping fuel ..just a prob i had when i rebuilt mine

                    Comment

                    • bssford460
                      • Mar 2007
                      • 10



                      #11
                      OK, well i checked some more. i checked the gaskets and the kit i got did come with the correct gaskets. so that isnt it. i think found a small peice of an old oring where the needle needs to seat and thought well thats it for sure. Nope, i was completely amazed that that was not the problem.
                      so im pretty sure that there are no vac leaks. the float needle is seating. the floats have been adjusted numerous times, i even called skidim and they told me exactly how to set them. i seem to have the proper gaskets.
                      and the fuel is not dumping in the secondaries, its on the primary side. but its just running out of the 2 silver things that look as if they point down the barrel of both sides of the primary side, i think they are called booster ventuires in the documentation i have seen.
                      i think when the guy gets back in town that my bro took that carb too he his gonna take it back to him and get him to go through it again and make sure it works before we get it back.
                      no worries though, this is a looong project we've been working on, when we took the boat out we had a vibration so i've had to take the prop to our local prop shop to be reworked, the guy said it was in pretty bad shape, but no where near unfixable.

                      in other news my brothers supra seems to be going good, the only problem is the packing nut needs to be tightened a touch, and we have to take the back seat out and the floor board out just to get to it to adjust it. that will be a pain. anyway thanks for the help guys.
                      and if yall think of anything else on the carb let me know. i'll let ya know how it turns out if the guy can get it fixed.

                      Comment

                      • freddyms
                        • Jun 2005
                        • 28

                        • Acworth, GA


                        #12
                        you might have already checked this but my old ski tique would do almost the samething. it was the needle seat was not all the way secured, or your mechanic friend stripped it and it felt tight when it may not be causing fuel to slip through the threads and overfilling the bowl.

                        Comment

                        • pj
                          • Oct 2003
                          • 323

                          • Rochester, MN

                          • 1991 SN 1996 SN

                          #13
                          I had the same issue on my '91. it was the needle and seat as well
                          Once you have tasted flight, you will forever walk the earth with your eyes turned skyward. For it is there you have been and there you will long to return. - Leonardo De Vinci

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