1980 CVX 18 alternator replacement.

[JThomas36]

Looking for a new alternator for my 1980 merc 260 .  5.7L    The unit I just removed looks to be original or close to it.  It has a 4 wire configuration.  Any suggestions on a good replacement with the same wiring configuration would be appreciated

[fireman24mn]

Replace it with a newer 3 wire. Just make sure it is marine rated.

[JThomas36]

Which wire goes away?  I see the newer units have 2 wire ( purple / red ) like mine.   Is the third wire going to be the orange wire in my case ?

[Plugcheck]

I would recommend a new one wire, marine rated, alternator.    Get rid of any external voltage regulator.   Db electrical, marine parts.com, numerous places sell the standard Delco Remy design.   The marine version has screening to prevent vapor ignition.    Let me know if you need wiring assistance

[JThomas36]

Ok, gonna need some more help here.   First pic is my original alternator cleaned up.   Finally got some numbers off it so I could order the correct replacement.  The 2nd pic is the DB replacement (4 wire ) unit worked awesome for a month and then ran fiery hot and quit.. 
 I found this replacement for my Motorola 8MR2024F, its 7466N - 94a  from strerndrive replacements.  I need help with what wires are going to the new red and black.   I believe my Battery wire (orange) is going to new alt terminal marked BAT.   Can you advise me on the red and black wires and my existing wires ? What one goes away ?

[Plugcheck]

The big bolt, marked B+, is the main charge output and connects to the battery with a larger gauge wire(I use 6-8 gauge).   The red wire is the sense wire used to determine what the voltage regulator(internal) to to be set at.   The black wire connects through a lamp, then to switched battery.   This provides the alternator warning lamp.

[Plugcheck]

Just wanted to add some additional comments.  Some folks just put a ring terminal on the red wire and put it on the same terminal as the battery connection, others may run a longer wire to the dash area to insure the remote area has full charging voltage.  Sometimes to insure audio power amps for instance have a bit higher voltage.     Either way, use a high quality voltmeter to check the alternator is charging at approximately 13.8 volts.    Can vary a bit, but big differences would indicate a problem.  Also insure the alternator light works properly, key on not running it should be lit.   It should go out when engine is running.   Good indicator belt drive to water pump is intact as well     good luck, let us know how it turns out

[JThomas36]

Thanks Plug check .. worked perfectly.   My biggest concern was Purple, exciter wire and wanted to make sure I got that right.  As described, 13.8 on the meter.Thanks again.   Appreciate the help