Alternator overcharging

[docofthebay]

I have an '88 with the twin 350/260hp engines. My starboard engine is overcharging to about 17.5 volts. Can the voltage regulator be changed by itself,or is it integral into the alternator and the whole thing needs swapping? Thanks!

 

[Boatingnut]

More than likely, it is an internal regulator. Two options: buy a new marine alternator, or, have this one rebuilt at a reputable shop that deals with MARINE alternators. I have had several rebuilt over the years with excellent results.

 

[fc3]

Yes, the regulator can be replaced. It's attached to the alternator. The regulator, brush holder, and brushes install as a unit. There's a seal on the regulator; therefore, do not use an automotive regulator. It's a simple swap. Last regulator I bought was about $70. Still have it, they don't go bad that often.

You probably have a wiring problem with the red "sense" wire. Check that you have +12vdc at both the red and purple wires before you go spending money. I'm betting on the sense wire.

Best regards,
Frank