Alternator

[grizzreaper]

I have a 1984 3.0 140 HP mercrusier . it can with no alternator or starter. Starter I hooked a old one I had with no issues. I have two mercury marine and a Wilson which I think is a automotive one. First picture has two post and three black wires.two wires on one post and a single on a smaller post. 2nd picture has two post with empty bigger post and a small single wire on the smaller post.there is two more wires one is reddish n the other is blueish gray. On the motor I have a purple wire, black wire, and a orange and red/purple wire connected together . serial on motor is 6783746. Which alternator should I use n how to wire to charge batteries. Thanks in advance.

 

[alldodge]

They both "look" like Mando ALTS because both have regulator wires coming out of the top

https://www.mercruiserparts.com/bam/...y/30893/963/70

 

[Bt Doctur]

Both look like Mando`s, the lug on the right is output (orange), Red should be the sense and the other one should be excite(switched 12v with the ign switch)

 

[grizzreaper]

Ok thank you. So I looked on a diagram. So the orange that is spliced with the red/purple I should unsplice. Put the orange wire on big lug, then the purple/red with reddish wire and purple with blueish gray one.

 

[alldodge]

Wiring diagrams

 

[grizzreaper]

Ok thank you. Since there is spot for the ground. I assume I just ground it to the bracket on the alternator. I have no clue on how to wire this. If it wasnt for iboat I would be in big trouble

 

[alldodge]

The Black wire is ground, and is connected to the stud on the top left on back of alt

 

[grizzreaper]

So to clarify this. Post with nut should be the Orange Battery. Then the Lil post with a transformer thingy post is the ground. The red wire is the sense and other is the excite. There is no other post or wires on here. I included a pic. Sorry to beat a dead horse but this wiring is so confusing when you don't know

 

[alldodge]

I would agree with your assessment. Do you know that the alt works? If not connect the orange last, and do check by turning power on excite lead (then back off) prior to connecting orange. I'm looking for a short

 

[grizzreaper]

Ok thank you. I assume it does work. Thanks again for your help

 

[grizzreaper]

Mando 55 amp

Not sure where my orginal post went. But I have a 55 amp Mando alternator. It's a J1171 with Mercury Marine pt# 11449 or 11448 not sure the tag is marked up. There is one big lug with bolt, one smaller lug with bolt and one wire with plug/butt connector. Trying to figure out what wire goes where. The motor is 1985 3.0 mercrusier 140 go. Thanks in advance

 

[grizzreaper]

I do have a book but it doesn't say what goes where. My ? Is which is a Excitation wire, b sensing wire. It has three wires but book shows only 2. So where would the purple go, red/purple and the orange go. Thanks agsin

 

[GA_Boater]

Not sure where my orginal post went.

Found it and merged the two threads.

 

[grizzreaper]

Ok thank you. That wiring was for the other alternator I put on. I want to put this Mando in the boat for the just in case. All three wires come out of the casing. One wire is going to big lug, another is going to smaller lug and one doesn't go anywhere. Maybe I am not reading something right, can someone send what lug and wire is what. Thanks again.