I've read many times that modern manufactured regulators should be avoided if possible. For me generators are kind of an obsolete tech curiosity interest I guess. There's no reason to use a generator over an alternator any more than driving a 60 year old car in the first place. It's a hobby. But they sure can try one's patience.

The regulator internal relays need to have their point surfaces dressed periodically as part of regular maintenance, or there WILL be trouble sooner or later. A couple times a year probably wouldn't be too often. High humidity esp. causes both ignition points and regulator points to corrode. In the case of the regulators a regular flat ignition file will not fit. Curved jewelers or riffler files used parallel to the relays are shown in the manuals. Emery paper or sandpaper works great in a pinch but ruins the point surfaces soon after if the manufacturers could be believed.

Been fighting this for some time. Had generator rebuilt by local guy. Had it back a couple of times and it is working. Regulator died. Replaced it with one form local Car Quest store. It worked for a while. Got one from Rock Auto. It didn't work. Got replacement from Rock Auto. It didn't work. Got a US made one from EBAY. It works. Almost wants me to go to an alternator but not quite yet. Learned a lot about how to test the generator on the car. Shop manual and an ammeter helped a lot. Generator putting out 30 amps and red light goes out. All is well. If old cars were easy it would take all the fun out of it.