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  1. #1
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    Merc 250 gear issue?

    2021 merc 250 4 stroke. While on plane all of a sudden I hear a beep and it seems to drop into neutral. Engine doesn’t cut off. I end up dropping the shifter into neutral, wait for the engine rpm to settle and then I put the shifter right back into forward and get up to plane speed without issue. Happened 3 times today. Any ideas on why this happened?


    Thank you

  2. Member
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    #2
    i believe they have a lot of issues with the electronic shifter and they are on back order so many have failed --search for threads about the shifting mechanism
    Last edited by mactlman; 11-06-2022 at 09:43 AM.
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  3. mikesxpress
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    #3
    Shift actuator issue.

  4. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #4
    While a Shift Actuator problem is POSSIBLE, these dual-sensor, gear-driven devices don't normally just arbitrarily "shift into neutral". So posts #2 and #3 are not real PROBABLE.

    Actuator problems are also not really that common- we do see SOME that fail (often where impact has occurred previously).

    Get it in to your dealer so that they can read the G3 Full Reports- and note that a Shift DEMAND sensor fault is a completely, and totally different device.

    I would be looking for wiring for the shift demand sensor that is not properly tie-wrapped behind the intake, perhaps allowing harness leads to chafe against a bolt or the block.

    If you would, please take a few moments to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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  5. Member
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    #5
    Quote Originally Posted by EuropeanAM View Post
    While a Shift Actuator problem is POSSIBLE, these dual-sensor, gear-driven devices don't normally just arbitrarily "shift into neutral". So posts #2 and #3 are not real PROBABLE.

    Actuator problems are also not really that common- we do see SOME that fail (often where impact has occurred previously).

    Get it in to your dealer so that they can read the G3 Full Reports- and note that a Shift DEMAND sensor fault is a completely, and totally different device.

    I would be looking for wiring for the shift demand sensor that is not properly tie-wrapped behind the intake, perhaps allowing harness leads to chafe against a bolt or the block.

    If you would, please take a few moments to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!
    my apologies.

  6. Member 21xTriton05's Avatar
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    #6
    Could be as simple as a wore out cable or it's not adjusted right. Either way, get it to your dealer before any damage happens.

  7. Member
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    #7
    It’s at the dealer as of yesterday Thursday. It has 57 hours and garage kept. Wiring looked clean at first look. No codes shown in the diags. Took it out on the water with the laptop connected in recording. Recreated the issue twice. It basically happens instant when taking a solid impact hit from a wake. Mystery issue reported back to the Mercury engineer team. Not obvious issue and could be boatless for a while. Very depressed as I had to tell a high school a team I can’t captain for them. BTW serial number 3b016286

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #8
    Well- here's something to check (feel free to pass it along):

    Sometimes the shift demand switch harness is not routed/tied to the harness and ends up rubbing against the block or one of the stainless bolts on the block. This can result in intermittent signals and/or shorts, and depending on the exact wire involved, the PCM may not immediately recognize a short (it may actually see it as a change in demand parameters... ie: an attempt to shift).

    MOST I've seen logged a fault that helped to identify the problem. This particular item would be consistent with your "hit wave" description.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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