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  1. #1
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    Engine Cuts out / chugs at 3000 RPM

    Hello all,

    I have a strange issue with my Merc 125. Once I get to about 3000RPM, the engine cuts for about 1 second then kicks in for about 1 second, then cuts.....I can't keep it over 3000 RPM. If I keep it at 2800 RPM, it runs fine.

    I think it's a safety limiter of some sort. I have enough oil in the reservoir. Maybe something with the neutral safety switch?

    Would it be safe to run the engine that high out of the water with water flush muffs on? I could try disconnecting the sensor.

    Any other thoughts?

    Thanks

    Aaron

  2. Member
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    #2
    do not rev that high out of water look for blk yellow wire on over rev module should be mounted along with oil warn module
    .................................................. ...the scariest thing in life is the unknown ...................................

  3. Member
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    #3
    I found the Rev limiter. 821889A46.jpg
    Do you think the limiter is the defective part? Or some sensor telling the limiter to 'kick in'?

  4. Member
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    #4
    disconnect go run it
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member
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    #5
    There are several wires. black/yellow that is split and goes to two separate location; purple; brown, black. Which ones do I disconnect?

  6. Member
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    #6
    brn and black
    .................................................. ...the scariest thing in life is the unknown ...................................

  7. Member
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    #7
    I disconnected BLK/yellow, purple, and brown. It fixed the issue but couldn't turn the engine off. Put them all back and disconnected one by one. Brown. What's the risk of leaving it disconnected

  8. Member
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    #8
    no overrev protection
    .................................................. ...the scariest thing in life is the unknown ...................................

  9. Member
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    #9
    Thanks for the help

  10. Member
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    #10
    yes sir
    .................................................. ...the scariest thing in life is the unknown ...................................

  11. Member
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    Jul 2010
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    #11
    I still have a problem. I bought a replacement rev limiter from CDI. I installed it and tested the engine with water muffs on. It started fine but wouldn't turn off. I disconnected it, reconnected it and same result. I put the old one back on. It started fine and stopped fine. I kept the brown wire disconnected. I tested it in the water, it hesitates a little during launch and through about 3500 RPM but runs at nearly full speed. It also turns off fine. Checking the level of oil, it is getting oil (I was concerned they was why the rev limiter kicked in in the first place). This hesitation started after the problems with the Rev limiter. I replaced the plugs and same result. I am going to run another test today with it completely disconnected. I expect the engine wont turn off (without using the kill switch). I am curious if I will still have the hesitation issue. I tried calling CDI Electronics but their number is disconnected and website can't be reached. I am waiting for Wholesale Marine to call me back.
    Thanks