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  1. #1

    Totally Confused after full build!!!! Wth? KEPT RUNNING!!!

    OK, guys i saved my questions. Tons of hours searching. Please shed some light. This my second post here.

    So my project when i bought it "just needed a battery" lol.

    Ok, full build, w/ factory components. 50 hours on a GP1200R 2000 model. Completely factory at purchase.
    D plated w/ chip, oil block off, primer kit, rebuilt carbs, and wave eaters. Other build parts are factory. IE pistons' rings, pins, clips... ect. Using only info from here and the manual.

    Today was "D" day so to speak. First try it fires right up, then dies. Not a problem, just prime and fired right back up. did this a few times to get things to seat. Really high idles too. Wasnt to bad at first.

    Here's the confusion. Another start up, and the engine just shoots to almost rev limit and would not shut down. Pulled the safety cord, pulled plug wires, pulled fuses, turned the fuel off, and disconnected the battery. And it just kept running.WTH? Im assuming until it ran out of fuel. Filled the garage with blue smoke < seams normal for a 2 stroke.

    Compression kept it running is all i can think of that would keep it running. I really hope all that hard work didnt go down the drain.

    Do you have any idea? At this time i have not tried to restart. Of corse its super hot right now.

    This is my first ski and first build on one. Proud of myself, but really confused! Ive built many motors of different sorts and never had one continue to run without spark and 12 volts. Please guys shed some light.


  2. #2

    Join Date
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    did you replace the crank shaft seals? If not I supect you have a crankshaft seal leaking air in to engine or a air leak around the carb/reed gaskets or base gaskets, most of the time it's the crank seals. Tommy Jordan
    Last edited by 2fast4u; 06-22-2014 at 07:05 PM.

  3. #3

    Join Date
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    Did you pressure test motor after rebuild?

  4. #4
    Quote Originally Posted by toyterrific View Post
    +1
    Did you pressure test motor after rebuild?
    I did not, and am not sure how. .... Plug it off and shoot air to it, and bubble test?

  5. #5
    Quote Originally Posted by 2fast4u View Post
    did you replace the crank shaft seals? If not I supect you have a crankshaft seal leaking air in to engine or a air leak around the carb/reed gaskets or base gaskets, most of the time it's the crank seals. Tommy Jordan
    Did not change crank shaft seals. Only fifty hours on them, i really thought they would be ok.

  6. #6
    Thanks for the info guys. I did end up trying it again. Super high idle but i was able to shut it down. It did however run on again. Really hope nothing is jacked. Compression test tonight. Will post results.

  7. #7
    Ok, so i went out to the garage to complete a compression test. Realizing i left the tester at work last week. Also found the oil block off plate sitting on the work bench. What a dummy i am!

    So could this be my air leak?

  8. #8

    Join Date
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    Still need to do a pressure test.
    Search for it under 2-strokes and how to.
    Buy or borrow one or make your own.
    Found one of my motors leaking at power valve cover plates. You never know until you test.

  9. #9

    Join Date
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    It would seem most likely to be an air leak, but you may also want to confirm that your throttle linkage is operating properly and if its got carbs, that the butterflies open/close smoothly. One of my butterfly shafts was sticking and that caused issues with engine speed. good luck michael

  10. #10

    Join Date
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    You also want the idle speed to be close, if it is too high it can lead to "lean runaway" which is what you had.

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