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  1. #1
    Member
    Join Date
    Sep 2011
    Location
    Chadbourn
    Posts
    25

    90hp mercury tilt/trim won't go up or hold up under a load.

    This problem just started out of the blue. It didn't give any initial problems before. And it happens time i put the boat in the water. So it will do it when cold or after running awhile.
    Here is what i know:

    When boat on trailer:
    1. The up and down function works fine on all 3 locations of the boat.
    2. The motor will hold up without leaking down for 1 day so far.
    3. The motor will lift up with me and my son standing on the lower unit fin, roughly 400lbs.
    4. I can't reproduce the motor going down on the trailer.

    When in water:
    1. While in water sitting still, the up and down works fine.
    2. While in water sitting still, the motor will hold up without leaking down.

    When in water driving:
    1. When i am going slow the motor will trim up and down.
    2. When i am going almost at breaking a wake, the motor will not trim up.
    3. When getting on plane, motor will not trim up. If i trim it up from a stop then try and get on plane, it will go down.
    4. If i trim motor up from a stop and "punch" the throttle it will go down.

    When driving on plane:
    1 When i am on plane, i can see the trim go up and usually it will hold.
    2. Down works fine on plane.

    I don't have any issues with the down part. It is my up side that doesn't move or hold under pressure of acceleration.
    Is there any orings i need to check the the valve body? If so can someone tell me where and what to check. My boat and motor is a 1999 Bass Tracker with a 90hp Mercury outboard, same year as boat. Thanks

  2. Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
    Posts
    13,938
    #2
    check o rings on manual release valve
    .................................................. ...the scariest thing in life is the unknown ...................................

  3. Member
    Join Date
    Jun 2021
    Location
    Orange City Iowa
    Posts
    1
    #3
    I know your post is old but did you ever find the answer on this? I just bought a boat and am having the exact same problem. Wanted to try to fix it before taking the shop bill. PLEASE any help is appreciated.