Thank you for clearing that up and the link. Will read the link soon.
As an update, the charge light seems to now be staying on versus being intermittent before. Volt meter readings verify that with light on no charging taking place. Will have to decide which route to go to correct issue.
So just to summarize, check if I have the facts right on the 73 Ford 4000
1. The charge light comes on after running for awhile. Periodically goes off or comes on.
2. Not running, but stopped when charge light was mostly off, then the resting battery measures 12.8 volts.
3. Not running, but stopped when the charge light had been on for awhile, resting battery is 12.4 volts.
4. When running, and charge light is off, you measure as high as 16.5 volts at the battery
5. When running, and charge light is on, you only measure 12.4 volts at the battery
5. All of this remained the same when a new voltage regulator was put in.
6. Took generator to a shop where it tested good.
7. There aren't any electrical problems other than the charge light coming on periodically - and that voltmeter readins seem to indicate that when the charge light is on the system is not charging. Tractor starter seems OK.
8. You are concerned that the charge light and voltmeter indicate that something is periodically failing in the charging system and want to fix it before it doesn't charge at all.
Is all that right? Did I miss anything?
rScotty