Motorola Alternator

[trenthightower@]

Hoping someone can help...? The alternator on my Yankee 30 died yesterday. I pulled it off the motor (Farymann L38M) but can't seem to find any information on it (not sure what to replace it with?). It's a Motorola Y3N3S. I do know that it powers the Tachometer. What I'm not sure of though is if it has an internal regulator or not? There were five wires hooked up to it. One to the battery, a ground, the Tach wire, then the other two I'm not sure of...? Do the other two wires come from an external regulator? I can't find one anywhere on the boat. Does anyone know anything about this particular model alternator? I'm at a loss for a replacement.

Thanks in advance for any information anyone is able to provide.

Trent

[GordMay]

I don't recognize the Y3N3S, but here's a typical couple of Motorola alternators, utilizing remote regulators:

[trenthightower@]

Thanks, Gord. Those do look similar to mine. I'm thinking mine is also externally regulated then (I'm kind of embarrassed that I don't even know this for sure). I've attached a picture of mine. Does this look to you to be externally regulated?

[GordMay]

yes, it does.

[Pete Mooney]

Hi Trent,
We have a Farymann engine with the same Y3N3S Motorlola alternator. We've had the external regulator go bad a couple of times over the years. (I think because the alternator was run while the batteries were disconnected). On the Prestolite website someone mentioned the "8MR2050FA (110-532)" as a replacement. (I haven't verified this information).

At present, our alternator is again not putting out any current. I would like to know if you did replace your alternator and the model number of the replacement?
Regards,
Pete


P.S. Thanks Gord May, for posting the schematic of the alternator

[GordMay]

Originally Posted by Pete Mooney

... On the Prestolite website someone mentioned the "8MR2050FA (110-532)" as a replacement. (I haven't verified this information)....

CORRECT: The 8MR2050FA is a 37 Amp 14V replacement for the obsolete Y3N3S.

Goto:
Heavy Duty Alternator Series, Prestolite / Leece-Neville

Specifically:
Product Specifications
And:

http://www.prestolite.com/literature...128_marine.pdf

[trenthightower@]

Hi Pete,

I did not actually replace my alternator. I took it to the local auto-electric guru. He tested it and it was fine. I had him rebuild it anyway cause it looked pretty bad. I also had him test the external regulator which was also fine. I eventually discovered the problem was with position #1 of my keyed ignition switch. Position #1 was what sent power to excite the alternator. I replaced the switch and everything work fine again.