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  1. #1

    Default how to test trim ?

    i have a merc 170 i/o the trim is stuck in the fully up position, bypassing the limit switch i hear the pump whirring when the down button is pressed, when the up button is pressed just a click. its an older pump with the solid metal reservoir. i disconnected the 2 lines rummin to the pump , the down buttom produces a stream of flid out one of the holes , however the trims down go down, any tips to help me test if its the pump or the lines or the trim arms ? i woudl hate to replace it all when only 1 part is bad,

  2. #2
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: how to test trim ?

    Hook the lines back up. Then when running the trim down, have someone bounce on the drive. Many people when they put the drive up hold the button till the pump boggs down. Fully pressuriezed and leave it that way for long periods of time. Then things stick.
    Next time you put the drive up. Hit the down button for a quick second to releave the excess pressure.
    If you head up to the Adults only stick, you can download an OEM service manual for your drive. It has all the troubleshooting details in it. With wiring diagrams for testing the solenoids.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  3. #3

    Default Re: how to test trim ?

    excellent, will try that, thanks

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