Yamaha 130 Rect/Reg Charge Issue

[Kola16]

1996 Yamaha 130TLRU serial: 6L1 L 308426 X

I am not getting a charge current to my battery. Both my multimeter and sonar agree with that. With everything turned off, my battery was reading 12.8 volts consistently. With the engine running for 5+ minutes at 1750 RPMs, it would only read 12.6 volts. The voltage on my sonar does not seem to go up while running at 4500 RPMs either. So I began testing my charging system.
- It seems I have a good AC voltage out of the stator from the 3 green wires with the engine running. I cannot remember the exact voltages. I also checked the resistance of the 3 green wires with the engine off and they passed the test.
- I then tested the diodes in the rectifier/regulator with the multimeter diode test. They all passed the test.
- I cleaned battery terminals and the grounds on the starter and the rectifier/regulator ground.
- I tried a different battery.
- I unplugged the red wire plug on the rectifier/regulator and tested each end with the engine running. The red wire coming directly out of the rectifier/regulator read 0.65 volts while running. Is that correct? I read someone said this should be 13-14 volts, but cannot find that in a manual. The other end of the red wire plug read 12.6 volts, which seems correct.

Anyway, figuring the rectifier/regulator was the issue, I went to just go order the part ($150). I then made more questions for myself. The original part number is 6R3-81960-00-00 and superseded by 6R3-81960-10-00. The 6R3-81960-10-00; however has an extra red wire coming off the rectifier/regulator that mine does not have. My rect/reg has one red wire, where the part I'm supposed to replace it with has 2 red wires. So what is this second red wire for? Is it for a second battery bank? I am assuming I can just cap it off if I do not need it, correct?

Thanks for any help!

 

[Kola16]

So I found this trying to figure out what the spare wire is: "The OEM version for some applications of the RM30428 will have an extra red wire used for voltage sensing. The RM30428 does not include or need this wire, as the voltage is sensed directly from the battery connection. If your original had one it is no longer necessary. You can tape or heatshrink the red wire on the motors' harness, and tie it up securely." Just FYI RM30428 is the part number of an aftermaket rect/reg for my engine.

As far as I can see there is no red wire on my engine's wiring harness, beside the one already connected to the rect/reg. So if I bought a new OEM rect/reg, and it came with 2 red wires, would it still work if I did not connect the second red wire? Or would I need to do something with the second wire?

 

[Kola16]

Picked up the OEM part 6R3-81960-10-00 today. It had the spare red wire. I put it on the engine and just left the spare red wire on the rectifier/regulator unconnected. The engine is charging the battery now! All is well. Still not sure what the purpose of the other wire is.