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  1. #1
    Petty Officer 2nd Class
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    Default Is my alternator/battery guage working correctly?

    As it states i am trying to figure out if my alternator/battery gauge are working correctly. Recently i replaced my battery on my boat as the one that had been sitting in it throughout the winter died. Originally i just recharged it after it was winterized but it always seemed like after it sat for a few days that it had a hard time starting. And when i would get into the boat after it sat a few days and would turn the key the battery gauge would read just above 8 volts until it turned on and i raised the rpms the gauge would rise up to about 13(center point on the gauge) volts and after it ran a little it would start up fine. Well i finally replaced the battery because i went to start it the other day and it barely turned over.

    After putting the new battery in i noticed the gauge would only rise up to about the 13 volt mark once the rpms were raised? With my experience with cars that have had battery gauges as well as general charging knowledge, they would immediately jump to 13-14 volt mark once started and my understanding that an alternator is regulated at 14 volts running, and that the battery would be 12 volts stagnant and not running. Why does my battery gauge only go up to the 13 volt mark after the rpms are raised and not while its just idling
    ]
    NOTE: this is only upon start up, once the boat has had the rpms raised it will stay at the 13 volt mark idling or not until turned off and restarted)?

    Is this normal or does it sound like there could be a low rpm charging problem? Could my belt being too loose cause this i can just about flip the belt totally upside down, however it doesnt squeak or seem to slip? I havent had a chance to attach a voltmeter, but i was wondering if these gauges are pretty accurate or if i should be looking into testing it?


    ALSO: what weight gear lube should i put in the reservoir, and what type of power steering fluid should be used?

  2. #2
    Fleet Admiral
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    Default Re: Is my alternator/battery guage working correctly?

    using a known good volt gauge/tester attach it to the battery, record reading. Start engine to 1500 rpm record reading.
    engine run reading should be higher than static reading
    NO PERSONAL QUESTIONS, THIS IS WHAT THE FORUM IS FOR.

  3. #3
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Is my alternator/battery guage working correctly?

    Quote Originally Posted by paczowski123 View Post
    As it states i am trying to figure out if my alternator/battery gauge are working correctly. Recently i replaced my battery on my boat as the one that had been sitting in it throughout the winter died. Originally i just recharged it after it was winterized but it always seemed like after it sat for a few days that it had a hard time starting. And when i would get into the boat after it sat a few days and would turn the key the battery gauge would read just above 8 volts until it turned on and i raised the rpms the gauge would rise up to about 13(center point on the gauge) volts and after it ran a little it would start up fine. Well i finally replaced the battery because i went to start it the other day and it barely turned over.

    After putting the new battery in i noticed the gauge would only rise up to about the 13 volt mark once the rpms were raised? With my experience with cars that have had battery gauges as well as general charging knowledge, they would immediately jump to 13-14 volt mark once started and my understanding that an alternator is regulated at 14 volts running, and that the battery would be 12 volts stagnant and not running. Why does my battery gauge only go up to the 13 volt mark after the rpms are raised and not while its just idling
    ]
    NOTE: this is only upon start up, once the boat has had the rpms raised it will stay at the 13 volt mark idling or not until turned off and restarted)?

    Is this normal or does it sound like there could be a low rpm charging problem? Could my belt being too loose cause this i can just about flip the belt totally upside down, however it doesnt squeak or seem to slip? I havent had a chance to attach a voltmeter, but i was wondering if these gauges are pretty accurate or if i should be looking into testing it?


    ALSO: what weight gear lube should i put in the reservoir, and what type of power steering fluid should be used?
    What engine and year we working on, do you have a Voltmeter or Ammeter on the dash> HUGE difference.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  4. #4
    Petty Officer 2nd Class
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    Default Re: Is my alternator/battery guage working correctly?

    SOrry i always forget to put my motor info down. 1998 4.3 190 hp mercruiser. Yes its volts.

  5. #5
    Petty Officer 2nd Class
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    Default Re: Is my alternator/battery guage working correctly?

    im assuming i should just hook a voltmeter to it, but what volts should i see coming from the alternator? While idling, as well as with a slightly raised rpm?

  6. #6
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Is my alternator/battery guage working correctly?

    At idle, you will see from 13V on up, at 1500 you should be showing around 14.8. Check at the battery, and at the instrument in the panel.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

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