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Thread: Engine Seize?

  1. #1

    Engine Seize?

    Can a '95 750 engine seize, break free 20 minutes later, start again run for 30 seconds seize again, break free 30 minutes later, spin free and show 120lbs compression in all 3 cylinders?


  2. #2
    Moderator beerdart's Avatar
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    Yes it is called a lean seize from lack of fuel or oil. Most of the time it will cause piston and or cylinder damage. Running lean will cause excessive heat and the piston expands and sticks in the cylinder.

    PS Welcome to the hulk.

  3. #3
    I would think the compression would be alot lower. Any thoughts?

  4. #4
    Race, wreck, repeat delagem's Avatar
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    Yup, I did this repeatedly before I learned how to align the intake manifolds on the 92 and 93 650.... Once it frees up it will run fairly normal, then sieze again when it gets hot/lean enough. Do it enough and you'll start to lose compression.

    As previously stated, in my case it was an intake air leak causing the PTO to run hot, the piston grew faster than the cyl expanded, 4 corner seizure. Cools down, runs again.

  5. #5
    Is there any way to tell what cylinder squeaked without pulling the heads?
    Compression is Front 120, Center 115, Rear 115. The rear plug looked cleaner than the other 2 but still has a little brown color on intake port side.

    Oil pump fail? Any chance motor will be OK without tear down. If carbs are cleaned and premix is used instead of oil pump? Will the crank be damaged if I do not remove the oil pump and simply let it run dry, or is it a must to install block off plate?

  6. #6
    As far as I know the carbs have never been off this motor. All the paint is intact and looks like it was painted with the carbs installed.

    The ski was running great, no hesitation, excellent throttle response ran over a series of big wakes and the motor squeaked. Would not turn over for about 20 minutes. When it did break loose it ran for about 30 seconds and locked up again.

    I took it home and have not run since, just did compression test.

  7. #7
    Race, wreck, repeat delagem's Avatar
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    Quote Originally Posted by jsl750&slt750 View Post
    As far as I know the carbs have never been off this motor.
    I think we know why you ran lean! Time to pull the carbs and clean the filters, check the diaphragms, replace fuel lines, put in new fuel pump, etc....

    If you don't have low compression, I don't know how to see which piston squeaked without tearing it down, but I'd be tempted to just clean the carbs, and run it....

  8. #8
    Quote Originally Posted by delagem View Post
    I'd be tempted to just clean the carbs, and run it....
    I'm down for that I'll give it a try. if it works GREAT if not where is the best place for a shortblock?

  9. #9
    Who has the best shortblocks?

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