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  1. #1
    kman's Avatar
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    Top speed drop-off

    I have a 250X with only 9 hours. It used to do 65-68 easily (top speed recorded is 70). I took it out the other day on fairly calm water and and couldn't get more than 60. Stayed mostly at 59. RPM was only roughly 7300-7400 and boost was 8-9 PSI.
    Any ideas??


  2. #2
    BR549's Avatar
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    replace your spark plugs

  3. #3
    ercBOOSTED's Avatar
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    check your oil. If it got in the intercooler, you have to pull it and flush it. Same thing happened to me. I was only running 61.7 for a minute till I flushed the intercooler. I pulled between 2-3 quarts out. Gained a bunch back real quick. Check the oil often cause right now gas has been getting in the oil and raising the level. R & D is coming out with something to fix this, but right now its on you to keep it right. Do a search to find out about getting a better reading on oil. The rubber nubs up top of the dip stick are actually pushing the oil around and giving unaccurate readings. good luck man!

  4. #4
    kman's Avatar
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    Thanks for the help!!

  5. #5
    Mine did the same thing w/ 14 hours, was down top end and rpm's, replaced the plugs w/ CR9EIX's and problem solved...

  6. #6
    kman's Avatar
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    Top speed drop-off - UPDATE

    Changed the oil (was overfilled). Took out the intercooler and the fins had foamy oil on them. Cleaned it out with gas, washed, and dried.
    Took it out today and it did the same 59MPH, 7150RPM, 8PSI boost.

    Why is my boost only 8 PSI and and RPM's only 7150???
    Haven't changed plugs yet but I can't see this being the problem at 9 hours.
    Checked supercharger belt and tension and I don't see any problems. Also had the BOV off when the intercooler was out and it seems to seal OK with good spring pressure.

  7. #7

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    Grey. relief valve it has worked its way loose and is bleeding boost off. You can either block it off or take it apart and adjust it. Opinions will vary on what to do.

    Jason

  8. #8
    Beagleman62's Avatar
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    Quote Originally Posted by kman View Post
    Changed the oil (was overfilled). Took out the intercooler and the fins had foamy oil on them. Cleaned it out with gas, washed, and dried.
    Took it out today and it did the same 59MPH, 7150RPM, 8PSI boost.

    Why is my boost only 8 PSI and and RPM's only 7150???
    Haven't changed plugs yet but I can't see this being the problem at 9 hours.
    Checked supercharger belt and tension and I don't see any problems. Also had the BOV off when the intercooler was out and it seems to seal OK with good spring pressure.
    Kman,
    You are very low on boost. JW is right about the bov. It's leaking or are you sure you got all the hoses tight when you put the intercooler back in?
    Where you only running 8 lbs of boost before you pulled the intercooler?

  9. #9
    Diablo's Avatar
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    I have the same problem..

    i checked cooling line, oil level, plugs evry thing was good. when i open intercooler i found leak on it, i replace intercooler seal.

    befor the boost was 9.


    Tomorrow i will test my sky.

  10. #10
    Ok I had the same problem and it was infact the BOV leaking boost....to find out the easy way if this is also happeing to you take the hose off the BOV in the back of the intercooler the gray plastic one hook up the garden hose flush kit and start the engine and DUH turn the garden hose one then listen to the rear area of the intercooler and if you hear air leaking that is your problem if not it could be the other BOV which does blow air out when not on the throtle

    So hook the hose back up to the plastic BOV and then un-hook the hose on the other BOV you should hear air comming out of this one if you are not giving it gas...so rev it up a bit not too much you should hear this one close up and stop puting out air....this is what I did to find out my 2nd BOV the metal one was not closeing...so I replaced it

    Try that and good luck

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