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  1. #1
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    150 four stroke trim stop

    Is there anyway to disable this? I have been driving boats for 20 years and know when to stop trimming my motor. I don't want the boat telling me how much I'm allowed to tim up. I have the single trim cylinder too so it's just in the wiring that stops it.

    My gauge was reading off when trimmed all the way down so I tried moving the sender around a little bit to see if that would fix the gauge and allow me to trim it up more while on plane. Now it trims less and I lost 5 mph and 350 rpm.

    The boat always ran best at max up trim and if I even slightly trimmed down it lost major speed and handling. I would love to trim up a little more to try and get the bow up more, because I feel it dragging the front, and way worse now after it doesn't trim up as far anymore.

    Or does anyone have the wiring diagram for this so i can figure it out?

    2015 trx189 2015 mercury four stroke 150

    thanks

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  3. Member
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    #2
    Quote Originally Posted by gonefishin1012 View Post
    .. I don't want the boat telling me how much I'm allowed to tim up..
    Then fix the boat.

    Mess with the motor and you can kiss your Merc warranty goodbye.

  4. #3
    Normally the sender is adjusted so that when the motor is trimmed fully down the gauge indicates fully down. If the sender is adjusted properly then when the gauge indicates the motor is at the top of the trim range the motor will be at the top of the trim range. Which according to the Mercury Owner's manual is 20 degrees Up from being fully down.

    I see that your model motor is limited so that it will not go into the tilt mode (beyond 20 degrees Up) when the motor is running much beyond a fast idle speed. I am guessing that the limit is set by the motor recognizing the sender position but this is just a guess on my part. If my guess is correct then you can "fool" the motor into thinking it is fully down when it actually is not. Trim the motor a few degrees up from its lowest setting and then adjust the sender to the full down position. Then try the motor and see what happens.

    Or you can install a wedge between the transom and the motor so that the motor is at a different (greater) angle to the boat than it would otherwise be. The trim gauge will then correlate correctly with the motor but the motor will have a greater Up trim capability with respect to the boat.

    http://thmarine.com/reverse-transom-wedge.html


  5. Member
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    #4
    I thought about the wedges. Just didn't want to pull it out of the water. I keep it in a slip on a lift.

    No matter how much I messed with the sender it won't read fully down.

    I don't care about the warranty. It's out in a couple months anyway. I'm going to be sending the ecu for tuning after I get this fixed too. Just wanted this fixed.

  6. #5
    I just went to the parts book. Your model uses a trim limit module. I don't have a Mercury Service Manual and therefore can't determine if the module is adjustable or not. I suspect that Mercury does not want it messed with. I also suspect that the trim gauge gets its information from the limit module but maybe not.

  7. Member
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    #6
    Thank you everyone for your input. I really want to completely disable this. I got it back to within 1mph of what it was. I just really want to figure out how to get rid of this. A wiring diagram or a wire that controls this would be great. Again I don't care about warranty.
    Thanks

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #7
    Please see the Forum Announcements, and be sure to provide the REQUIRED info when posting. Thanks!

    A couple of very important pointers:

    -This engine uses a DIGITAL trim sender. It's adjustment should not be altered, as it can cause malfunctions and substantial loss of performance.

    -TRIM angle (maximum) is PCM Controlled. This is hard-coded programming, and if you attempt to accelerate beyond approximately 2500 RPM's (or trim beyond the max position), Engine Guardian will occur. This is a SAFETY measure. Have an Authorized Mercury Dealer verify that you are achieving the maximum 20 degrees of trim angle.

    -A "Trim Limit" kit is also available to install. This is actually a TILT limit kit (designed to stop the engine trim at a fixed position, so as to prevent contact with other objects that might damage the engine).

    -Transom Wedges are not acceptable for use (per Mercury Service Bulletins).


    Dual Mercury Master Technician- for Mercury Outboards, Racing & Mercruiser Sterndrives in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 40 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  9. Member
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    #8
    Listen to DON motors are too expensive to replace,

  10. Member
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    #9
    Thank you for the replies. I'll verify if it's going to 20 degrees or not.

    Honestly I don't care about any warranty.

    My boat actually doesn't plane off trimmed down as good as at halfway trimmed up. I never have a reason to trim it all the way down because of this. I really want about 4-6 degrees more up trim.

    What's the problem with transome wedges?

  11. Member
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    #10
    Don,

    Pardon my ignorance, but if the OP has the Mercmonitor, could this simply be a trim calibration issue? I know the manuals walk the owners through it, but I am not sure if that would affect actual trim or just indicated trim?
    Last edited by cfm56doc; 01-04-2017 at 12:58 PM.
    2013 Z118 w/Merc 150 4S

  12. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #11
    MercMonitor only calibrates the "displayed" trim (does not alter the PCM or trim sender functionality).


    Dual Mercury Master Technician- for Mercury Outboards, Racing & Mercruiser Sterndrives in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 40 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  13. Member
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    #12
    Quote Originally Posted by EuropeanAM View Post
    MercMonitor only calibrates the "displayed" trim (does not alter the PCM or trim sender functionality).
    Thank you sir.
    2013 Z118 w/Merc 150 4S