I have a 77 M885 got it about a year ago and have slowly been fixing this and that as time allows. My current problem is it maybe over charging and I can't figure out why. So this is what I have, at idle I get 12.5-13 volt at the battery which is to be expected with a 70s charging system, but when you bump up the RPM I quickly get 15.7 volts at the battery. What I have done so far; if you unplug the regulator then it drops to battery voltage, a new regulator gave me 15.6 volts at the battery so I put the old one back in and returned it, I checked and cleaned ground to the regulator even ran a jumper to negative on the battery no change. I don't want to swap alternators just to test mine and have no wish to tearing in the wiring harness with out good reason. So are they known for running a little hot in the voltage(what is your voltage at the battery)? I know that this is not ideal but is it really a problem. Oh and yes I do have a the amp gauge bypassed. Thank you and this is a great site wasted many an hour on it.
P.S. I have been thinking about just putting in an AC Delco 12si and being done with it, has anybody done this?
P.S. I have been thinking about just putting in an AC Delco 12si and being done with it, has anybody done this?
Last edited: