140 Voltage regulator adjustment

I'm getting this out of the way right at the beginning.. NO, I am NOT putting an alternator on it so don't bother suggesting it.
Ok, so I just completely rewired my new-to-me 140. It charges again and the lights work! I checked the voltage at the battery with my digital meter and it read 15.0 with the tractor at full throttle after it had been running for about 3 hours (at full throttle the entire time, it's my lawn mower). At idle it shows 14.7. Yeah, it's a little high, but should I even bother messing with it? How exactly can I back it down just a touch? Is there a good written procedure for adjustment?
 
Voltage regulator adjustment instructions can be found in mid 1950s to early 60s Motors Manuals (a Brand of thick repair instructions for
cars) Libraries have them and you can copy the related sections. Because the exact mechanism may vary for OEM, or replacement VRs, that is
the best solution. Jim
 
Before you get too deep with this recommend
you repeat your voltage readings with a
known good ANALOG voltmeter.

Reason: Digital voltmeters - especially
cheaper (< about $200) ones - are notorious
for giving erroneous readings on old
generator/point ignition systems. You may
we'll find your charging voltage is
actually OK.

That said, 15.0 volts at governed RPM is a
bit high but not excessive. If your
tractor is used only occasionally and for
only an hour or two at a time, operating it
at 15 volts won't hurt a thing. Just keep
an eye on the electrolyte level in the
battery and top off with distilled water
when needed.
 
How exactly can I back it down just a touch?
I believe the 140's started out as 6 volt, and somewhere in the 60's changed to 12 volt. With the readings you mention, I'm assuming yours is 12 volts. Do you have a 12 volt generator and a 12 volt regulator? Sometimes folks will take a 6 volt setup and tweak them to run a 12 volt system. That setup many get tweaked to the high side.
There are other reason a system can charge high. Grounds are critical, and must be clean and tight. If the generator and or regulator can't "see" the battery clearly, ie: bad grounds, mis-wireing, etc, the generator may run wild. High voltage, but usually low amperage. Does your generator get really hot as in too hot to touch? That's a sign it's having a problem. Fields full grounding, can't sense the battery, bad battery, etc.

Tweaking the output of a regulator should really be done on a test bench, to eliminate some of the reasons that can be occurring on a tractor that I mentioned above.
May wanna just try another regulator.
 
If you search for:

delco-remy service bulletin

you will find some instructions for servicing voltage regulators.
 

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