MF135 voltage regulator question

I have a Continental gas 135 with a generator, and I have been having some intermittent charging issues. I've gone through the wiring and cleaned some bad connections up, and tested the generator and everything seems to be in order, most of the time. I don't have the L hooked up on the VR as there is a lot of homebrew lights wiring on this, and I wanted to eliminate any of that, and thought that it should still work without it. I've had this tractor for about 10 years, and use it regularly and recently developed this charging issue.

I've been working on this the last few days as I was baling some hay, & ran it with a volt meter hooked up so I could watch the battery voltage as it operated. Periodically, it will just stop charging and sit at the battery's voltage of 12.5V until it begins to charge. I found if I tapped on the voltage regulator, it'd start charging again. So I lightly sanded the points on the relays. No effect.

I'm not real savvy on generator/VR setups. I can't imagine what could make the electromagnet stop pulling the points in, short of a bad connection or ground or something, but like I said, I checked the wiring using an OHM meter, and the VR box seems to be making good contact to the frame, unless there's a better way to ground it than the mounting screws, and tapping it is making the ground better. It's an aftermarket VR I put on a few years ago.

Thanks for any advice. I don't really want to put an alternator on it.

I ran out after work and took another stab at this after studying the schematic and trying to get an understanding of how it works.

I sanded all the terminals, and the VR mount bolt flange and panel where it mounts. I also pulled the cover, and hooked up a voltmeter to the battery and started the tractor. It turns out it looks like it works for a bit, then the coil the F terminal (the normally closed contacts) looks like it stays closed, but actually must be open. If I press is open or closed, the generator will start putting out again and the relay will chatter likes supposed to, but after a bit will pull in again and sit idle, but not make electrical contact. The contact pads look good, and I sanded them a bit yesterday. The voltage seems to climb up to 15+ volts, maybe 16 briefly before it opens when it's working; not sure if this is normal, but seems pretty high to me.

I'm a little baffled, because when I ohm through it they're good, and I cycled them over and over and never saw an issue with resistance. But I guess its new voltage regulator time.

Any advice or guidance on material to read to understand how this works appreciated.

They are (were) totally rebuildable, at
least on a bench. A new one from NAPA is
about $80. I bought two from this site
(junk). The one from NAPA has been fine
for the last year. One wire alternators
ARE available,reasonably.

The following is an interesting read.

http://www.navioneer.org/riprelay/The%20Na
vion%20Files/Delco_Remy_Generator_Regulato
rs.pdf
Untitled URL Link

Thought I'd post an update. I bought a new voltage regulator, a
Sparex, S.43247 from Napa. The last one I bought was maybe 8 years ago for maybe $20, and that's the one that wasn't working. They look identical, but the new one works as designed with the points for the Field opening much more quickly and not getting stuck. I don't see anything obvious with the old one, but I'm not gonna lose sleep over any it more.

Thanks, Stan, for the link.

No problem.