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  1. #1
    Member
    Join Date
    Oct 2018
    Location
    Manitoba
    Posts
    71

    Merc 4-stroke analog trim gauge - needle resting position?

    Hi all, just bought a trim gage for my boat, it's Merc P/N 79-895292a41 which is the only White/chrome Merc gauge I could find listed as being compatible for my 2012 115efi four stroke and matching my existing gauges. Brand new out of the box, the needle was pegged at "up" and after installation this doesn't change upon powering up the unit. Is this normal? Wondering if I have a bad gauge, I'm questioning if needle should be at full "down" position at rest (?). Here's the troubleshooting I've done thus far that's making me question the gauge:

    -Confirmed gauge is wired correctly. Power/ground to gauge are good
    - Jumped the gauge’s signal post to ground, observed the gauge needle go to full “down” which supposedly (per googled test procedures) confirms the gauge itself is OK (?)
    -Confirmed there is continuity in the trim signal wiring from the sender to back of gauge
    - Also, unplugged sender wire at the motor and measured ~0.3ohm resistance in wiring from motor harness to an intermediate connection near the gage
    - Confirmed that sender resistance changes (via DMM) when trimming the motor up/down. From ~0 ohms (down) to ~135 ohms (up)
    -Measured voltage between gauge signal post and gauge ground post while trimming motor – it stays fixed at ~7.7V

    Any help would be appreciated!

    Thanks
    - Rob

  2. Member
    Join Date
    May 2011
    Location
    Spangle, WA
    Posts
    6,180
    #2
    Might try the 4-stroke forum 3 below this one and include engine serial number.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax


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