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94XP won't start in water?

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  • #16
    Sounds like you had a classic lean seizure with lots of detonation. I seriously doubt your crank was effected, or your piston contacted the head - most likely the detonation just ate away at the piston rim (especially in front of the exhaust port I bet) and the ring may have even broke...but bits are sure to have bounced around and pitted the heck out of the head. Most of the time the damage to the head is not deep enough to need a new one, and it can be remachined. You at the very least need to clean up the head and do a top-end job. The crank should at least be fully inspected, if not replaced. You will not be far away from the price of a whole new engine.

    As for the cause, I would be suspecting either the carbs needing to be rebuilt, or some obstruction or air in the fuel lines.

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    • #17
      Did I read that right you were 1/4 turns out on your high speed? You should have high speed out at least 1 1/4 that might be why you lean siezed.

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      • #18
        Hi Bryan,

        I just received an SBT exchange motor for my lean seized 94 XP 657X. Upon inspection, I noticed a couple of differences from my original. The SBT case does not have any drain plugs and the pulse fitting is located on the PTO end instead of the of the mag end. Are these any big deal?

        Thanks,
        Steve Kinney

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        • #19
          Sea-Doo updated the design on the case and got rid fo the POINTLESS drain plugs (ever try to reach them with the engine installed?!), and switched the location of the pulse fitting several times. It's no big deal, just use a new line of fuel hose for the pulse line.

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          • #20
            Hi Bryan

            I was out at the lake today going through the break in procedure on my new 657X SBT and attempting to set the low speed jets (both 75). At about 1-5/8 turns out the PTO plug had a chocolate brown color on the rim, however the mag plug was still clear. I had to adjust the mag carb out to about 1-7/8 turns before parts of the plug rim appeared brown. It looks like 2 turns might do the trick but I ran out of daylight. At the risk of sounding stupid, is it OK to have different adjustment screw settings for each carb? Will the fact that I'm running the SBT break-in oil in the gas tank (using oil injection system amount) affect the appearance of the plugs?

            Thanks again,
            Steve Kinney

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            • #21
              Yes, it is fine to have different settings on different cylinders - in fact it's expected. You will not, however, be able to do your final tuning until after break-in, and after you've cleared out all the extra oil.

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              • #22
                Re: 94XP won't start in water?

                This sounds like an electrical problem too me... The resistance provided when in the water is just enough that the weak spark described is not enough. Out of the water, there is no resistance- faster @ crank-up better fuel atomization etc... Just a thought. Yeah? Nay?.... Peace, CG (Tidal Wave Water Sports)

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                • #23
                  Re: 94XP won't start in water?

                  This in no way sounds like an electrical problem to me.

                  Here is what I see.

                  Is it possible that the first motor had debris left in the cases from changing the pistons or a bearing failure, that came up and battered your mag piston? Or was it just running so lean and you ran it so long that it disentergrated the top of the mag piston? Why would you run it that hard if it were lean enough to do that much damage from detonation?

                  On your new motor.
                  Adjusting low speed adjusters are for getting the motor to idle correctly without loading up and to accellerate sharply. The lows are not for getting a good color on the sparkplugs. That is the function of the high speed adjusters after you get it to accellerate using the low speed adjusters.

                  Start out too rich. I mean way too rich. Open the high speed adjusters 2.5 turns out. It sould burble and bog and not get max rpm from being too rich. This will tell you that you have a large enough main jet in the carbs. If it won't get too rich, install larger jets. Now, start closing those high speed adjusters until it starts to gain rpm. You are now getting closer to having it adjusted correctly. Keep closing until it gets max rpm and just starts to lose a little rpm. At this point, stop and open the high speed adjuster about 1/4 turn and start doing sparkplug color checks. Adjust each carb seperately until the plug for that clyinder is a nice brown color. Both carbs do not have to be set the same. When you finish adjusting the highs, you will need to re-adjust the lows and the idle speed.

                  Never go any further than you have to to get a plug check. In other words, if it is too lean, don't go far enough to damage the piston. Just go until it hits max rpm and stop and check the sparkplugs. Never idle the boat while doing plug checks. Ride full speed and pull the tether and coast to a stop and check them.
                  Bill O'Neal <br>
                  WCM
                  <a href="http://www.watercraftmagic.com"

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