Alternator Wiring

[BigWeakSauce]

1974 Mercruiser 165 Inline 6. Original alternator only has two ports: positive and negative... new alternator listed as an aftermarket specific to this model has a purple and a separate red wire with odd connectors coming from it. Nowhere to attach those and they are too short to reach across the engine to the power supply anyway.
My questions - what are those wires, do I need to have them connected since my boat doesnt need them? Assuming theyre required to close the alternator circuit but I have no idea what to do with them.

 

[alldodge]

The ALT has a built in regulator
Red connects to 40 amp breaker or on to solenoid with other Red wires.
Purple connects to key ON ignition + side of coil

 

[BigWeakSauce]

When you say solenoid are you talking the starter relay or the ignition coil? I do have a breaker but cant tell what is running to it. The starter relay has the main red, starter solenoid red, and a third unknown red already on it. The unknown might be the alternator but havent made it that far yet.

 

[alldodge]

Red starter relay with other red wires are
Purple on + side of coil where Tan wire is

 

[BigWeakSauce]

So those wires on the alternater only serve to power a built in component? So theoretically I can just jumper from the red cable thats going to the positive alternator port to avoid having to run another red wire, and just run one purple into tan relay port. I feel like that wont work but I dont see why it wouldnt

 

[alldodge]

No

You do that and it will kill your bat, and may even back power your motor so it won't turn off (never tried to do that). While you can connect the Red to the main terminal, the purple needs to be turned off/on, otherwise the ALT is always on.

Maybe exchange that one for a one wire ALT