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  1. #1

    1997 XP Rotex???????

    I have just been talking to the seller of this ski but havnt got a clue what he is on about would someone please be able to enlighten me


    Link below

    "Seadoo Xp 1997 extremely clean. 800 CC 2 STROKE, New seat cover, Jet Pump in excellent condition, paint & plastics in like new condition , Carbs rebuilt. Roughly 150psi per cylinder. Great compression, Real Strong Spark Dose not run at the moment I think the Rotex valve has something to do with it, I do not have the time to mess with it.
    Retail VALUE = 2,175 Comes with single place trailer.. Thanks for looking!!!!"

  2. #2
    KrunchovXPL-GTX-RX's Avatar
    Join Date
    Mar 2009
    Aiken, SC
    By "Rotax" valve he is talking about the Rotary Valve.

    The R-valve is on a shaft mount across the short axis of the engine and is driven via a pinion gear off the crank. If that gear strips out (which happens sometimes) it will get that valve out of time (and even lock the engine up) and it will run poorly or not at all.

    However, I would not expect one to push that kind of compression with an R-valve out of time (it would be like having a broken reed on a 951 IMO).

    The boat is in nice shape and it would not be a bad deal for someone who can do all the work themselves, even if it needs an engine. The '97 XP can be a fun boat but it was underpowered and far surpassed by the '98-'03 XPLs.

  3. #3
    Is there a way i can tell if its the R Valve

    If it is the R valve do i have to pull the engine to replace the part

  4. #4
    KrunchovXPL-GTX-RX's Avatar
    Join Date
    Mar 2009
    Aiken, SC
    The Rotary valve is not going to fail. Well, not like you think. It is a metal disc with a "window" cut into it. As it spins that window opens on the front and rear intake port to allow fuel and air in and then closes the port to allow for primary compression.

    If anything is wrong with the valve itself it was caused by something getting in the intake and damaging it (a bolt perhaps). If this were the case the engine would likely not turn over or make some unusual noise.

    If the valve is out of time there is something wrong with the shaft (likely a stripped pinion gear) and that would require pulling the engine and splitting the cases at the least.

    The valves can wear out and groove where they run up against the case and the cover (think of your brake rotors when you need new pads and they are all grooved up). I do not have a lot of 787 experience so I am not sure if a grooved up valve would keep it from running though it would have sealing issues and may not run as well as it should.

    How to tell? I will say that I have seen a rotary valve that was almost 180 degrees out of time and the engine would not only start but would run down the lake. It was not as strong as it should have been, but it would go. In fact, it had normal compression so that may not mean anything after all.

    I do not know if you can see the valve through a carb. If you can, you could get a rough idea if it was in time or not. Or even spinning at all. Other than that, I can not think of anything other than pulling the intake.

  5. #5
    Update to what he said to me

    The Mechanic

    he dosen't think anything fell into the carb because the motor turns over freely. He said It could be done by strong back pressure? I dont have all the answer because it hasnt been pulled apart.

  6. #6
    2000 GPRXP 4tec shooter98xpl's Avatar
    Join Date
    Dec 2005
    Charleston SC
    You can check the rotary valve by taken the carbs off, then taken the rotary valve cover off and looking inside. May need a light and mirror. I had a rotary valve strip before. Fortunately its not as bad as you think. The ski will turn over but will never start up. Also, with him trying to turn it over, he may get some of the brass clippings in the crank bearings. You would have to some how get a vacuum hose up in there and suck it all out, but in the end, you are better off pulling that motor and doing it right.
    That ski looks awesome, but with it not running, I'd only pay around $500 to $600 for it.

  7. #7
    lextoy's Avatar
    Join Date
    Jan 2007
    Brigantine, NJ
    you can get that engine rebuilt, top notch for 1500-2000.
    or you can get a rebuid from SBT, for around 750.
    since it sounds like you are going to pay someone to fix it
    i would pay no more than 800 for the ski as is.
    you might get lucky and its not as bad as it seems, a good mechanic could get it goin for 300 bux.
    do you already know who you are going to get to fix it??
    ask to take the ski there and get an estimate on repair.
    then buy the ski based on that price.
    you dont want to invest more than 2k in the ski total.
    for a person who will do the work themself , that is a MINT lookin ski, totally worth it.
    but if you are payin for the engine work, might not be worth it.

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