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  1. #1
    Member
    Join Date
    Oct 2016
    Location
    DeWitt, IA
    Posts
    350

    Vacuum or pressure test lower unit?

    What would be the proper test to make sure seal(s) are good on a Yamaha (SHO) lower unit vacuum or pressure? I would think maybe depending on the way the seal lips are facing the results may be different...Also what would be the specs be of a good/bad test?

  2. Member
    Join Date
    Jul 2016
    Location
    TN
    Posts
    144
    #2
    I have a device that pressurizes the lower unit you should pump to about 15 pounds of pressure let is set for about 3 to 5 minutes if it holds your good. If the oil is milky its pretty certain you have a leak.

  3. Member
    Join Date
    Apr 2007
    Location
    lucasville, ohio
    Posts
    726
    #3
    Vacuum doesn't work correctly. Ive tried.

  4. Member cwilt's Avatar
    Join Date
    Jan 2007
    Location
    Homestead, FL
    Posts
    11,227
    #4
    Quote Originally Posted by richhat52 View Post
    I have a device that pressurizes the lower unit you should pump to about 15 pounds of pressure let is set for about 3 to 5 minutes if it holds your good. If the oil is milky its pretty certain you have a leak.
    i just changed my water pump and read in the manual that 10 psi is max for pressure. and remembered this thread.
    2008 Ranger 178VX
    150 Yamaha V-max

    GO Fins!!!