Alternator Question

Boilers2000

Petty Officer 1st Class
Joined
Jun 15, 2018
Messages
252
Alternator question

I want to install a blue sea ACR and want to fully understand the wiring of the boat. One question I have is around the wiring of the alternator. I have a 92 4.3LX. I have 4 wires coming from my alternator..my question is around if my understanding of these wires is correct. According to the service manual:
1. Black - ground
2. Orange - output wire. This wire is shown running back to the stater solenoid and I believe is what passes charge back to the battery so the battery can recharge.
3. Purple - Excitation Lead. This is shown running to the ignition coil and I believe provides current for the spark plugs
4. Red/purple - Sensing Lead. This is shown just running to the molex of the wiring harness. I believe this is what runs to the dash gauge for voltage reading.

Is my understanding correct or am I missing something.

Thanks in advance!
 

Boilers2000

Petty Officer 1st Class
Joined
Jun 15, 2018
Messages
252
Posted on another thread but didnt get a response, thought I move to here to see if any of the speedy responders knows.

I want to install a blue sea ACR and want to fully understand the wiring of the boat. One question I have is around the wiring of the alternator. I have a 92 4.3LX. I have 4 wires coming from my alternator..my question is around if my understanding of these wires is correct. According to the service manual:
1. Black - ground
2. Orange - output wire. This wire is shown running back to the stater solenoid and I believe is what passes charge back to the battery so the battery can recharge.
3. Purple - Excitation Lead. This is shown running to the ignition coil and I believe provides current for the spark plugs
4. Red/purple - Sensing Lead. This is shown just running to the molex of the wiring harness. I believe this is what runs to the dash gauge for voltage reading.

Is my understanding correct or am I missing something.

Thanks in advance!
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,453
click to enlarge. the "sense" is a constant 12v supply, the "excite" gets power from the key switch in the "on" position and also power the coil
 

muc

"Retired" Association of Marine Technicians...
Joined
Jul 7, 2004
Messages
2,259
#3 is what powers the volt gauge
#4 is always hot battery voltage

not sure what a “molex” is?
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,453
Really , look at the wiring . The sense is always hot and the excite GETS its power from the key switch because that purple wire also powers the coil
 

jbcurt00

Moderator
Staff member
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Oct 25, 2011
Messages
25,197
Boilers, dont start multiple topics about the same subject

Merged

If you think a topic would be better served in another forum, ask a Mod to move it for you, dont start a 2nd topic.

8 or 9hrs between posting and getting a reply isnt unusual, it is the weekend. Members have boats and lives, so they might be busy elsewhere until dark, or later.....
 

Boilers2000

Petty Officer 1st Class
Joined
Jun 15, 2018
Messages
252
Sorry JBcurt, wasn't sure of the proper merging protocol and/or how to reach a mod.

Bt Doctur, I think my thought is aligned with you...so then does the orange wire create the path from alternator to starter solenoid to battery. Trying to trace the path current flows from the alternator to recharge the battery.

Muc, moles is what air was calling the ten-ish pin plug that most of the engine wires terminate to.

Thanks again everyone
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,453
it goes from the alt output directly to the starter solenoid main battery post sometimes thru a 90A fuse link.
#16 in my link
 
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