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  1. #1
    Member Macsimus's Avatar
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    Compression Testing?

    <1B961164>
    250 Optimax

    I have read the thread in the FAQs and the doc in the Mercury service manual and still have a couple of "first-timer" questions.

    1. What is the suggested way to "orient the throttle shutter to wide open" and maintain it there during the test?

    2. Can anyone recommend a compression tester that will work for the Opti? The service manual recommends a Snap-On motorcycle compression tester that doesn't seem to be available any more. It's been replaced by a EEPV503 but $250 is a little steep for this shade-tree guy.
    Last edited by Macsimus; 05-18-2022 at 06:54 AM.
    There was a time that I didn't fish but I cannot remember it.


  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    Best way is to hold the roller open with your thumb.

    Brand really isn't that important. You can get a decent compression tester from an auto parts store or several thousand online tool suppliers for less than $50.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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  3. Member Macsimus's Avatar
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    #3
    Thanks Don.
    There was a time that I didn't fish but I cannot remember it.