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  1. #1
    Petty Officer 1st Class FJ_Russo's Avatar
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    Default 85hp Johnson v4 Compression #'s ?

    So I did the compression test as outlined above I have only had this motor for about a month and havent had a chance to put it in the water as there is about 8" of ice standing between me and it I was just wondering if these #'s sound good or about average for a 1975 85HP Johnson V4 engine.

    Cylinder #1 115PSI
    Cylinder #2 116PSI
    Cylinder #3 119PSI
    Cylinder #4 120PSI

    Thanks for the info guys!

  2. #2
    Moderator ezmobee's Avatar
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    Default Re: 85hp Johnson v4 Compression #'s ?

    Sound great to me. From what I understand, the actual numbers are not really that important as the testers aren't real accurate in that regard but they ARE consistant. Yours being over 100 and so closely matched is a very good thing.
    1976 18' Starcraft SuperSport 90HP Evinrude
    Restoration thread http://forums.iboats.com/boat-restoration-building-hull-repair/18-starcraft-supersport-restoration-357767.html
    1966 16' Starcraft Jupiter 85HP Johnson
    Restoration thread http://forums.iboats.com/starcraft-boats/ezmobees-1966-jupiter-338633.html sold

  3. #3
    Petty Officer 1st Class FJ_Russo's Avatar
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    Default Re: 85hp Johnson v4 Compression #'s ?

    Thanks EZ! I was looking for factory #'s just out of curiousity but I coudn't find any.
    So the Starmada does venture out into the world of Iboats. I thought we all just hung out there like a cult or something

  4. #4
    Moderator ezmobee's Avatar
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    Default Re: 85hp Johnson v4 Compression #'s ?

    Nah, I'm just stalking you
    1976 18' Starcraft SuperSport 90HP Evinrude
    Restoration thread http://forums.iboats.com/showthread.php?t=357767
    1966 16' Starcraft Jupiter 85HP Johnson
    Restoration thread http://forums.iboats.com/showthread.php?t=338633 sold

  5. #5
    Petty Officer 1st Class FJ_Russo's Avatar
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    Default Re: 85hp Johnson v4 Compression #'s ?

    LOL Well I guess thats cool. I mean I always visioned my stalker being 120lbs blonde hair blue eyes and female but maybe we can work something out.... Your not far off that right EZ??

  6. #6
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    Default Re: 85hp Johnson v4 Compression #'s ?

    There are no published factory #'s that I know of. As long as they are 15 psi with in each other should be okay. Last time I seen a spec published was in a 1967 Evinrude snowmobile service manual.

  7. #7
    Petty Officer 1st Class FJ_Russo's Avatar
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    Default Re: 85hp Johnson v4 Compression #'s ?

    ok well then looks like I'm good to go. I was Just do some routine checks and dreaming of spring. Thanks for the info Boobie!

  8. #8
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    Default Re: 85hp Johnson v4 Compression #'s ?

    That engine when new probably had close to 125 lbs compression, so your current numbers are just fine. Also, it is not unusual for the compression to vary a few lbs from one head to the other, due to the way the blocks were machined at the factory. Looks normal!

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