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  1. #1

    are compression tests bad for a ski?

    Was wondering because your starting on a cold engine without any oil in the cylinders??


  2. #2
    04gtxsc's Avatar
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    You dont start the ngine when doing a compression test>

    Besides how is this any different than actually starting an engine?

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    Fastest in my cove sfackett0's Avatar
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    it shouldnt be that big of a deal, once you start cranking up the engine the oil pump will supply oil to the engine. Now if theres no oil in the ski then you have bigger problems than no compression.

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    njk4o5's Avatar
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    its hard to tell. every engine i compression test is destroyed already

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    steach's Avatar
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    Quote Originally Posted by njk4o5 View Post
    its hard to tell. every engine i compression test is destroyed already
    That's too bad

    When you test compression the other spark plugs are in (unplugged) and the throttle is held open.
    The normal gas/oil is flowing just no spark...Perfectly normal.

    Make sure the battery is fully charged. (I've seen a weak battery cause people to take apart a good motor)
    Last edited by K447; 06-27-2013 at 10:06 PM.

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  9. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by golferdude View Post
    Was wondering because your starting on a cold engine without any oil in the cylinders??
    Engine does not have to be cold. You can warm it up first, if that is your preference.

    What kind of engine are you taking about? 2 or 4 stroke?

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  11. #8
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by golferdude View Post
    2stroke
    2-stroke engine should always have some oil in/on the cylinder walls, from the last time it was running.

    If the oil is good quality it will coat the cylinders and crankcase bearings, and still be there when you next crank it.

    Peak pressures inside the combustion chamber when checking compression are actually fairly low, since there is no ignition and combustion pressure to force the piston rings against the cylinder walls. So the piston rings are not highly stressed during a compression test.

    As long as there is some minimal existing oil lubrication inside the engine it should be fine.

  12. #9
    Ive always heard to test the compression cold with WOT. Otherwise the numbers arent as accurate.

  13. #10
    ford man's Avatar
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    i just did a compression test on my 2000 GS(718cc 2 stroke) i got 115 psi i know their low numbers but is it more important to have higher #S with a spread or lower #s within 10 % of eachother
    thanks cody

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