Mercruiser 140 Alternator Replacement

[piasajake]

I have a 1985 Mercruiser 140 I am replacing the alternator on. The existing alternator is a 3 wire Delco style. I purchased the wrong alternator. I bought a 1 wire Delco style. They basically look the same except for the 2 wires that come out of a plug on the alternator which is capped off on the new 1 wire style. I was wondering if the new 1 wire style can be used on my engine or be converted? Also, if I am able to use the 1 wire style, what are the other 2 wires used for?

 

[piasajake]

Re: Mercruiser 140 Alternator Replacement

I may have found out my answer myself, but other input would be welcome. I was informed that I can just use the 1 wire connection and cap off the other 2 leads going to the connections for the old alternator. They are evidently sensors for the ignition and charging systems that are internally built into the new alternator.

 

[Robj]

Re: Mercruiser 140 Alternator Replacement

Hello I posted the same question a few days ago but for a Volvo, and only got one reply from Bond-o who basically confirmed what I already thought. Run the big wire from the battery to the main terminal at the back of the alternator. Cap off the other two wires, they are not required.

Unfortunately have not had a great deal of input from others lately on this site. So I went to another site, and within a few hours someone confirmed the above. So just hook up that one wire, cap off the other two and you are good to go.

Have a great day

Rob.

 

[piasajake]

Re: Mercruiser 140 Alternator Replacement

Thanks for the info Rob. I was hoping the one I got would work. I think help used to be more plentiful on here a while back too...

 

[Robj]

Re: Mercruiser 140 Alternator Replacement

I agree. Check out marineengine.com I think there is a Merc section. I go to the Volvo section. Have not had much luck here lately. Used to be much better even a few weeks ago. Just make sure it is a marine alternator.

Have a great day,

Rob.