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  1. #1
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    Lower unit leak down test?

    I think that’s what it’s called- when u pressurize the LU and check for leaks.
    Is the factory tool available and reasonable?
    Thx

    96 150 FastStrike

  2. Member
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    #2
    vacuum leak test maybe
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  3. SC Club Moderator ChampioNman's Avatar
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    #3
    Use a bicycle pump, I made one out of a floor style pump so I could use it while the lower is on the stand. Got a straight thru nylon barb and inserted it in the pump end and then used the hose from the lower unit fill pump. Screw into the lower unit and pump up first to 10 psi then 15 psi to hold for 10 minutes. For vacuum testing I use a Mytvac pump for bleeding brakes work great too! Pressure tester was about $18.00 to make.

  4. Ohio Fishing Reports Moderator omcforever's Avatar
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    #4
    Quote Originally Posted by ChampioNman View Post
    Use a bicycle pump, I made one out of a floor style pump so I could use it while the lower is on the stand. Got a straight thru nylon barb and inserted it in the pump end and then used the hose from the lower unit fill pump. Screw into the lower unit and pump up first to 10 psi then 15 psi to hold for 10 minutes. For vacuum testing I use a Mytvac pump for bleeding brakes work great too! Pressure tester was about $18.00 to make.
    Built mine just like Freds,,,,

    Age and treachery will always overcome youth and skill !!

  5. Sprint Boats Moderator Bassmeister's Avatar
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    #5
    Quote Originally Posted by ChampioNman View Post
    Use a bicycle pump, I made one out of a floor style pump so I could use it while the lower is on the stand. Got a straight thru nylon barb and inserted it in the pump end and then used the hose from the lower unit fill pump. Screw into the lower unit and pump up first to 10 psi then 15 psi to hold for 10 minutes. For vacuum testing I use a Mytvac pump for bleeding brakes work great too! Pressure tester was about $18.00 to make.
    Same here.

  6. Member
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    #6
    I’m confused about vacuum testing.
    I thought all I needed to do is make the L U is /is not holding pressure.
    Thx

  7. Sprint Boats Moderator Bassmeister's Avatar
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    #7
    The seals are designed to keep water out and gear oil in...proper testing means pressure and vacuum testing.

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    #8
    The driveshaft and propshaft outer seals will not be affected by a pressure only test, that's where the vacuum test comes in.

  9. Member
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    #9
    So when you pump up the lower unit are you using the upper hole or the lower drain hole. Is the lower unit gear lube left in the lower unit or drained before pressurizing it.

  10. SC Club Moderator ChampioNman's Avatar
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    #10
    Lower and drained.

  11. Member
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    #11
    Is there a good video showing how this is actually done?