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  1. #1
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    Default Connection diagram for a 4 wire alternator 4.3L merc alpha

    My son and I did not make notes of the alternator wire locations when we removed the alternator to have it rebuilt. Altrntr model 12174N 12v - 1996 4.3L merc alpha

    Alternator terminals:
    EXC =
    S =
    B =
    E =

    Wires:
    Red =
    Orange = Has the rubber protector
    Black =
    Purple =

    Could someone please help us connect the wires to the proper terminals?
    Thanks in advance.

  2. #2
    Moderator Don S's Avatar
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    Default Re: Connection diagram for a 4 wire alternator 4.3L merc alpha

    Attached Images Attached Images
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
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    Only forum/moderator issues will be answered in PM's.

  3. #3
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    Default Re: Connection diagram for a 4 wire alternator 4.3L merc alpha

    WOW Don. This is perfect! Thank you for your help.
    Alt is back on and appears to be charging but the output seems to drop a volt as the RPM increases. The belt was very tight and squeaky. I think the rebuild shop may have put on a larger pulley. Im pretty sure we got the belt on correctly. Do you have a diagram for the serpentine belt?

  4. #4
    Moderator Don S's Avatar
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    Default Re: Connection diagram for a 4 wire alternator 4.3L merc alpha

    Larger pulley won't do that. Are you sure you have the A and B wires hooked up right? If you do, take the alternator back and have him recheck it.
    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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