Electrical Question -- Alternator Wiring on Late 70s Mercruiser

[Twolane]

On a late 70s boat. Both the Mercruiser manual and a Clymer manual show a one wire alternator in their schematics. The boat has the alternator pictured installed however.

Discovered the discrepancy because the white spliced to yellow/tan/whatever it is wire seen in the picture had no destination as it was installed on the boat. So was looking to see where it went. In fact the entire harness pictured wasn't wrapped in the main harness to the alternator. Just piggybacked along side it with a few wire ties.

So am assuming someone replaced the original at some time with this one and used this harness to energize the alternator. Not a big deal really (at least not in any way I can think of). Nothing on the main harness was cut or altered in any way. Someone just made it work with the parts they had.

However; I've got a one wire Delco marine alternator here in some spare parts. Only thing it needs is a set of brushes. Any reason not to use that one and lose the extra harness? Or is there some benefit to the multi-wire alternator I'm not aware of?

 

[Bt Doctur]

Re: Electrical Question -- Alternator Wiring on Late 70s Mercruiser

not really, the 3 wire turns on instantly ,the 1 wire needs some rpm to get excited and start charging.

 

[Twolane]

Re: Electrical Question -- Alternator Wiring on Late 70s Mercruiser

not really, the 3 wire turns on instantly ,the 1 wire needs some rpm to get excited and start charging.

So it behaves like the single wire alternators that are common the automotive aftermarket? No real reliability difference, less strung wire, that's an easy choice. Will go with the original. Thanks. Can still keep the other for a spare in case ever caught out. Only have to run one lead to energize it.