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  1. #1

    Help! Seadoo XP floods out at idle.

    I have a 94 XP with a 657 that floods out at idle. I have been working on this problem for weeks and I can't get it to run correctly. At idle it loads up and if i shut it off after riding it, I can't restart it as it is flooded out. Here's what I've done so far:

    Checked compression and it's good.
    It has Strong Spark
    I rebuilt the carbs to include new kits, new needle and seats and I set the pop off pressure to 38 psi. Originally I set it to 25 psi. There are no leaks in the needle and seats or the orings that seal them.
    I checked the arm adjustment and it is in spec
    Checked and rechecked all adjustments

    The problem that I can see is that the carbs are dripping fuel from the high speed circuit. You can see the fuel dripping from the venturi at idle. The carbs were rejetted for altitude before i got the ski. I am at 6700 feet. I have noticed that the throttle stop screw (idle adjustment) seems to be opening the throttle blades more than i think it should be to stay running. I set the idle out of the water to 2900-3000 rpm. It idles well at first, then drops to about 1500 rpm after about a minute and thats when i can clearly see fuel dripping from the venturi. It's just loading up with fuel.

    Is it possible that the pilot jets are too small and it is forcing me to open the throttle blades too much, thereby causing the fuel to drip from the venturi because of the increased vacume in the throat, or is there something I am missing? Someone mentioned a "check valve" on the high speed circuit in another post when I did a search. Is that something I should check? Should i raise the pop off pressure? It ran fine before, so it seems like the jetting would be fine, but i am open to suggestions.


  2. #2
    Update:

    Well, I tried a leaner pilot jet to no avail. I checked the "check valve" and it was replaced at the time of the rebuild and is working fine. I am considering putting two check valves together. Anyone else tried that? I also raised the pop off pressure again, and no difference. I can't get a good setting on the low speed screws because the dripping fuel problem won't allow me to set the screws to a smooth idle. I am baffled. Why is this thing dripping from the inner venturi no matter what I do? Anyone?

  3. #3
    Set the pop off pressure to what the factory requires. Setting it so high will cause it to blow by internally when the the needle finally unseats.

  4. #4
    Yeah, unfortunately I tried that in the beginning. That's when I tried raising the pop off pressure as per others advice. I have tried different NS and about 6 different pop off pressure settings. It seems to run good for about 30 seconds to 1 minute and then starts dumping through the venturis again.

    One thing i have noticed, is that i have to turn the throttle stop screw in quite a bit for it to idle. I don't know if I have to do that to overcome the excess fuel that is dumping, or if it is causing it to pull from the high speed circuit because of the excessive vacume being pulled through the throat.

    One other possiblity...is it possible that the system is building too much pressure? I checked the fuel tank for excess pressure and that's not it. Has anyone ever opened up the fuel restrictor passage in a SBN or would that be a really bad idea? I'm afraid it will run lean on top if I reduce the pressure generated by the pump.

    Someone shoot me. This sucks. I considered myself to be pretty good with carb issues, but right now I feel like a total rookie.

  5. #5
    RumRunnerRon's Avatar
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    Quote Originally Posted by toxiceric View Post
    Yeah, unfortunately I tried that in the beginning. That's when I tried raising the pop off pressure as per others advice. I have tried different NS and about 6 different pop off pressure settings. It seems to run good for about 30 seconds to 1 minute and then starts dumping through the venturis again.

    One thing i have noticed, is that i have to turn the throttle stop screw in quite a bit for it to idle. I don't know if I have to do that to overcome the excess fuel that is dumping, or if it is causing it to pull from the high speed circuit because of the excessive vacume being pulled through the throat.

    One other possiblity...is it possible that the system is building too much pressure? I checked the fuel tank for excess pressure and that's not it. Has anyone ever opened up the fuel restrictor passage in a SBN or would that be a really bad idea? I'm afraid it will run lean on top if I reduce the pressure generated by the pump.

    Someone shoot me. This sucks. I considered myself to be pretty good with carb issues, but right now I feel like a total rookie.




    Ok first off I would not consider myself a tuner but from just reading this I can say there is not enough info to go off of. One question you ask about your jet sizing being to small but you don't list what you have them at. Post up you carb specs. Jet sizes, what needle seat and spring you are using, where you have pop off set at, etc... You may find after providing more spec info you get some input by the guys that do this. Just my two cents.

  6. #6
    flyin' the friendly skies airbornexp's Avatar
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    yes +1 Ron. We need to know a lot more of this skis history if we can make accurate recommendations. Has this motor been rebuilt? is your rotary valve set correctly? did you use a rebuild kit to rebuild/ clean the carbs? Why are you dripping fuel from the carbs and most importantly why is it coming out the venturi!? That shouldnt be happening! That motor must be full of fuel and loading the exhaust pipe too. Im kinda glad you havent been able to start it cause it sounds like a bomb ready to go off.

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