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  1. #1
    Petty Officer 3rd Class
    Join Date
    Oct 2009
    Lake Ontario

    Default 1980 Mercury 115 - Trim fluid?

    Hi everyone,

    I am getting conflicting reports on what I should be using for trim oil. My Seloc manual is saying 10W30? I very sure that is not what is in there right now. (It appears to be red)

    Also, it is my first year with this engine but the power trim was rebuilt last winter. Besides topping up the fluid level is there anything else I should do during the winterization or spring tune up procedure?

    Any advice is greatly appreciated.



  2. #2
    Petty Officer 3rd Class
    Join Date
    Mar 2004

    Default Re: 1980 Mercury 115 - Trim fluid?

    Your motor should have trim cylinders mounted outside of the transom bracket, and a pump mounted inside the boat. They take 10w30 motor oil. Often people put the wrong fluid in. It would be wise to purge the old out and put in the correct oil.
    As for winterization, stabilize the fuel, run the motor to get the stabilized fuel into the carburetors, fog the engine, grease the fittings,and change the gearlube.

  3. #3
    Petty Officer 1st Class lprizman's Avatar
    Join Date
    Jul 2009
    Rhode Island

    Default Re: 1980 Mercury 115 - Trim fluid?

    automatic transmission fluid is what I use,,not motor oil,,totally different composition
    Dusky 19 - CC - 150 Mariner - Rolls axle trailer
    up right and breathin,,,woohooooo

  4. #4
    Petty Officer 2nd Class
    Join Date
    May 2005
    South carolina

    Default Re: 1980 Mercury 115 - Trim fluid?

    They originally came with 10 or 20wt motor oil. You can use any low viscosity motor oil, Mercury's Power trim and Tilt fluid or hydraulic fluid. OMC used Dexron ATF. Many trim units have been refilled with ATF.
    I would recommend using the Mercury PTT fluid or 20wt motor oil.
    If you decide to go back to the Merc stuff you will need to drain, clean and refill the entire system. You can use mineral spirits to clean the system out.
    Merc recommended against using the ATF something about seals. I have known of many units using the ATF with no problem. So what you do is up to you. You should be OK with either fluid.
    You let the factory smoke out of it. All products have smoke installed in them from the factory. You can not purchase this smoke. The problem is, when you let the smoke out of it, the part is ruined and you have to get a new one. I wish I could find a place that sold the factory smoke.

    Never argue with an idiot. They drag you down to their level, then beat you with experience.

    3 X APBA Formula V Nat'l Champion
    APBA Formula V US-1
    It took me 29 years to become an overnight success.

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