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  • 1996 GTX Problems

    This is my first post. Glad to have run across you folks. Looks like a nice community with a lot of expertise.

    I have a 1996 Seadoo GTX that has the following symptoms:

    Ski starts normally. Intermittently will not accelerate through rave valve transition rpm approximately 3800-4000 rpm. This happens on a random basis with no consistency. If I increase the throttle the engine boggs down as if it were running on one cylinder. If I continue to "milk it" around this transition zone it will finally accelerate(sometimes it takes quite a while). Even when it does accelerate it's not what it used to be and gps top speed has dropped from 53-54 to 49-50. WOT is 6440rpm. Ocassionally at cruise speed the engine will bog back to the problem rpm(without releasing the throttle) and stay there until I "milk" the throttle again. Sometimes it will run quite a while without the bogging problem. Also every once in a while(last year) when running at WOT I would get a temporary burst from the 49 mph current operating max to the 53 mph max which it used to hit and there would be a temporary improvement in acceleration. I didn't notice the corresponding rpm increase so I can't provide and accurate number. Haven't seen the increase this year but I've only ridden twice.

    I've changed the NGK plugs numerous times, cleaned the fuel filter, changed gas, tried running in the reserve position, rebuilt the carbs and cleaned the rave valves twice(they had a good bit of build up which I removed). I haven't completely removed the water pressure regulator, but I popped off the top and it moves freely in and out. Red caps on all valves are flush. I have not trimmed the spark plug wires back 1/4 inch yet.

    Engine has 130hrs and has not been rebuilt. Have used Amsoil synthetic for the last several years. Impeller is clean and intake is clear. Cooling stream is minimal at idle, but increases substantially at cruise speed. Fresh water use only.

    Gut feeling would say it's a sticking rave valve not opening as it should above the transition rpm, however that wouldn't account for the engine bogging back to the transition rpm area from cruise without any reduction in throttle. The latter might suggest internal carb fuel filter clogging, although as I mentioned I have rebuild the carbs 2 years ago and the problem remained. Any suggestions would be greatly appreciated.

    One other question. When I removed the black cover under the instrument cluster on the pop up front storage compartment I noticed one of the molded screw in attach point had broken off. I'm not sure whether this hood is fiberglass or some sort of molded plastic. Any idea on the best type of adhesive to use for an attempted reattachment?

    Thanks for any suggestions!

  • #2
    Re: 1996 GTX Problems

    My guess is you have more than one problem.

    First test your compression. It should be no less than 150 psi per clyinder.

    I would test the fuel selector valve. re-check the pop off pressures and filters in the carbs. Test the water regulator. Test for voltage running and stopped at the battery to see if the rectifier is working.and the battery is getting charged as the motor revs up. Cut back the sparkplug wires as one bad connection at the sparkplug could cause all of these symptoms as it drops from running on two clyinders to just one clyinder.

    Last but certainly not least, you may be having a problem inside of the magneto housing, as the ignition pickup and flywheels are subject to failure on 1996 787 engines.
    Bill O'Neal <br>
    WCM
    <a href="http://www.watercraftmagic.com"

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    • #3
      Re: 1996 GTX Problems

      Seems logical to start with the plug wires and continue from there. I'll post the results. Thanks Bill

      Comment


      • #4
        Re: 1996 GTX Problems

        Did you miss the part that says "first, start with checking the compression" ???
        Bill O'Neal <br>
        WCM
        <a href="http://www.watercraftmagic.com"

        Comment


        • #5
          Re: 1996 GTX Problems

          Bill


          Since last post I have:

          1. Checked compression: 154 on both cylinders @ 800 feet msl.
          2. Trimmed 1/4 inch off both plug wires.
          3. Cleaned internal fuel filters on both carbs again. they had minimal contamination.
          4. Rechecked main fuel filter. It was clean.
          5. Removed and cleaned fuel selector valve. It wasn't clogged.
          6. Disassembled and cleaned water pressure regulator. It looked fine.
          7. Cleaned rave valves again.
          8. Checked rectifier. Battery voltage ~12.5 not running. As high as 14.02 revving.
          9. Removed and checked fuel tank baffel, checked botton screen and visually checked inside of tank.

          Still have same problem. When I first started ski this morning it bogged after warm up and milking the throttle wouldn't get it past 4000 rpm or so. I let it sit for 5 minutes tried again and it accelerated to speed. I've picked up 160 rpm and 3mph. WOT now 6600 speed 52mph. I ran several minutes at cruise then from cruise instantly dropped back to the 3800-4000 range as if one plug had just quit. I tried again and it wouldn't accelerate until I let it sit for a few minutes.

          Next I guess is the magneto check. I found this procedure for a 97 GTX. Is it the same for a 96?

          To Test the Spark Plug Trigger Sensor:
          Disconnect the Spark Plug Boots and Ground them out on the Grounding Posts.

          1) Locate the Deusche (Grey) Connector on the MAG. front cover.
          2) Using a meter set on the Low Ohms range, take a reading *between* the Black/Yellow Striped and White wires. Should be around 190-300 Ohms and no continuity to ground. (engine exhaust bolt)
          3) Set the meter on Low AC Voltage range.
          Take a reading *between* the White and Black/Yellow Wires. While cranking over the engine. Should be between .2~.5 VAC.

          Then I will remove the cover and check the bracket.
          Also I understand it's ok to unplug the red wire from the rectifier and run the ski with out damage. Just won't be charging the battery.

          I have a timming light with an inductive pickup. What would you think about hooking it to one plug wire at a time and checking the strobe output while riding. If I can duplicate the problem, no strobe would indicate no spark.

          Comment


          • #6
            Re: 1996 GTX Problems

            I'd disconnect the rectifier and try it.
            You probably won't find an intermittant problem with an ohmmeter.

            Comment


            • #7
              Re: 1996 GTX Problems

              Let me know what you find, especially after opening the magneto cover. You should closely inspect the flywheel for cracks or a magneto cup problem. They tend to come loose and wallow out the bolt holes. Also, upgrade to a 1997 or later ignition pickup as it is wise to do that if you have the cover off.
              Bill O'Neal <br>
              WCM
              <a href="http://www.watercraftmagic.com"

              Comment


              • #8
                Re: 1996 GTX Problems

                Try changing your fuel lines you may have some starting to go bad.

                Comment


                • #9
                  Re: 1996 GTX Problems

                  I have almost identical prob with my 97GTX. It'll go right up to 5000 rpm out of the hole WOT, and then bog until I "milk" the throttle and get it up to full rpm. I rebuilt carbs (but not needles), replaced all fuel lines and plugs, checked vent valves, cleaned raves. I tested fuel system by running hose directly to carbs from tank, but no change in performance. It'll go all the way to full rpm if throttle is steadily increased rather than stomped on. The plugs have a wet appearance after a ride. it doesn't stumble at idle. Low spd screws at 1-1/16 open, high speed screws at zero. ski has over 370 hrs if the electronic display isn't lying. Never rebuilt. never been hydrolocked. never run in saltwater. have not trimmed the spark leads. jet pump rebuilt last year. new battery and all grounding leads cleaned and tightened

                  Q1: Compression is 142.5 in both cylinders meas'd cold with a craftsman screw in gauge.--Is 150 psi truly the minimum needed, meaning a top end job is the only way??

                  Q2: The water regulator appears to leak a steady stream of water at idle thru a bottom hole, don't know what its doing at high rpm, but I see evidence of water spray or splashing the hull. Seat and trunk gaskets seem good. Missing a few rivets on buckled mats. Is some water running out of water regulator valve normal OR is this just another part of the problem??

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                  • #10
                    Re: 1996 GTX Problems

                    The engine can never run right with a leaky water regulator. Clip the sparkplug wires too while you are at it.
                    Bill O'Neal <br>
                    WCM
                    <a href="http://www.watercraftmagic.com"

                    Comment


                    • #11
                      Re: 1996 GTX Problems

                      thanks Bill re water valve. Is it more likely a bellows problem than anything else inside that valve?

                      again, what's your opinion on the compression 142.5 in both cylinders??
                      Last edited by 98xlt; 08-24-2005, 02:38 PM.

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                      • #12
                        Re: 1996 GTX Problems

                        I have no idea. Remove the top and look at it.


                        142.5 in each clyinder indicates that your compression is probably fine and your compression guage is probably reading at bit low or you are at a higher altitude than Sea Level.
                        Bill O'Neal <br>
                        WCM
                        <a href="http://www.watercraftmagic.com"

                        Comment


                        • #13
                          Re: 1996 GTX Problems

                          hoo-ya. that water valve bellows is definitely part of the problem.

                          I took the whole thing off the exhaust box and opened the cap. looked ok, but I saw evidence of rust around the edges, so I took the whole thing apart. The bellows had a huge rip in it on the underside and the lower bellows clamp was completely rusted away. no wonder it was leaking so.

                          Interestingly, the hard bellows cap that's threaded had 3 stainless steel washers set in it, that must have been placed to increase spring tension. Is that a factory calibration maneuver or somebody else????
                          hope i can get the parts quickly, summer's wastin'

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                          • #14
                            Re: 1996 GTX Problems

                            The three washers were part of a factory authorized capaign in 1997-98 era.
                            John Kubiak
                            Powersports Technical Training Professional
                            Las Vegas, Nevada
                            Sea-Doo Tech 13736
                            PWC Tech since 1988 (22 years)
                            PowerSports since 1976 (34 years)
                            NEVER BUY TIRES AT A "BLOW-OUT" SALE
                            Please do not use Private Messaging, use the forums.

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                            • #15
                              Re: 1996 GTX Problems

                              thanks John!

                              are you affiliated with any particular power sports shop in LV, or give referrals? respond or pm as appropriate.

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