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  1. #1
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    mercury 90 fourstroke not charging

    Mercury 90 fourstroke efi.
    Model 1f90413fy
    serial number 1b355828

    So it has stator style, wish I could swap a alternator I can do that. Any way to confirm this? Battery is showing 12.5 off (after I charged it and put back in), 12.77 with motor running

    thanks, goes down in the absolute worst freaking times.

  2. Member
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    #2
    any ideas. or just jerk the flywheel off and replace? I have no gauges for the boat, motor has a good bit of hours on it, guessing 3000. Just incase this is a part that could burn out after time? Thanks

  3. Member
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    #3
    I'd use a voltmeter to check the voltage on the yellow wires coming from the stator. Then check voltage on the red and black wires coming off the voltage regulator. The yellow wires will be AC voltage and you check it between each pair of wires with the motor running.
    Check all connections on charging system, the bullet connectors on the yellow wires have caused problems.

    I'm not sure what the voltage spec on the yellow wires should be but once you have some numbers someone here can give you the right specs.
    Last edited by Lowerider58; 09-13-2018 at 06:55 AM.

  4. Electrical/Wiring/Trolling Motors Moderator CatFan's Avatar
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    #4
    I would consider trying a different battery. 12.5V on a charged battery indicates a problem with it. A bad battery can prevent the charging system from raising the voltage higher. Certainly possible and maybe even likely you have a problem with both battery and charging system.
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  5. Member
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    #5
    You don't want to be jerking the flywheel off if not needed. Lot of work and they don't come off easily at times. Between the electrical generation system parts it is the least likely to fail.

    If the rectifier/regular provides substandard voltage then the procedure is to next test the input to the R/R. The input comes from the charging system coil within the stator. With the motor at X RPM you check for peak voltage output. If above specs the presumption is that the R/R has failed. Which is not all that uncommon. If the lighting coil is below specs then the stator is replaced. Not common for the stator to fail.

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #6
    Quote Originally Posted by yam911 View Post
    You don't want to be jerking the flywheel off if not needed. Lot of work and they don't come off easily at times. Between the electrical generation system parts it is the least likely to fail.

    If the rectifier/regular provides substandard voltage then the procedure is to next test the input to the R/R. The input comes from the charging system coil within the stator. With the motor at X RPM you check for peak voltage output. If above specs the presumption is that the R/R has failed. Which is not all that uncommon. If the lighting coil is below specs then the stator is replaced. Not common for the stator to fail.
    +1

    That is the general test procedure. However, you DO need to start with a GOOD, properly rated, and fully charged battery as STEP #1.

    Voltage Regulator is the most common area we see problems (and even that isn't real common on this model).


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  7. Member
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    #7
    thanks guys. It was the rectifer. 10 minute swap and charging 14.1 now.