Merc 255 MIE wiring Help

[legoman67]

Well, i am trying to wire my 1979 Merc 255 MIE Pre BIA color Code, but the problem is the previous owner upgraded the alternator, and i cannot figure out how to differ the 2. On the diagram it shows 4 wires comming off the alternator, the 2 main neg and pos, and then 2 others. I found out that with the stock alternator those other 2 connect to leads sticking out of the regulator on the alternator, but those leads arent there on this alternator. HELP!

wiring diagram also attached if needed.

 

[coastalcruiser]

Re: Merc 255 MIE wiring Help

your ignition coil is getting power from your starter motor in order to work.
What I would think is to take the positive, run it to your battery. and take negative and run that to the ground
Should work. if your battery says 13 volts your charging.
Also to double check what I said and post this in the electronic section and let Silvertip see.

 

[Bondo]

Re: Merc 255 MIE wiring Help

Ayuh,...

That looks like a self-regulated Alt....
If So,...
Hook the (+) to the wire that goes to the Batt. stud on the starter,...
And the (-) to Ground...

To other 2 wires will just be capped,+ taped back....

 

[legoman67]

Re: Merc 255 MIE wiring Help

the problem is the other 2 leads that are on the engine, that are supposed to attach to the alternator, i am not sure where to attach them. One is white and goes to the coil, the other heads up to the helm

 

[Bondo]

Re: Merc 255 MIE wiring Help

the problem is the other 2 leads that are on the engine, that are supposed to attach to the alternator, i am not sure where to attach them. One is white and goes to the coil, the other heads up to the helm

Ayuh,.... Like I said,...

"The other 2 wires will just be capped,+ taped back"....

 

[legoman67]

Re: Merc 255 MIE wiring Help

ok, ill just eliminate them, not to be stubborn, but why are they there in the first place with the stock alternator if they arent 'needed'?

 

[JustJason]

Re: Merc 255 MIE wiring Help

Originally the boat had a seperate regulator/rectifier.... a seperate box usually screwed to the transom. The new alternator is all 1 piece.