Not sure I'm following all of your checks.
I check the voltage at the solenoid. I have 12.7 at the left (pos to battery).
This is correct as it's the battery cable.
So this is with the key to the START position only and checking at the wire itself? Or are you checking at the post/stud on the starter relay?
Brown it goes from (.4 to 12.7) and changes every second. Sometimes it will hold the reading.
This is oddly inconsistent. At the wire you should read a relatively steady voltage, that could be dropping from a higher level to a lower level as the resistor wire under the dash heats up and reduces voltage. But it should not oscillate or go back and forth.
Loose connection? Bad wire? Neither will cause your battery to drain, but it can cause trouble down the road with slower starting perhaps.
On the starter side of the solenoid is (12.7).
Again, you're reading this with the key in START, correct?
Otherwise there should be no power there at all.
The key is off, all fuses pulled, the ele throttle solenoid is un plugged.
Since all the fuses are pulled then it has to be a drain on the main Black w/yellow wire. This usually means it's the alternator.
The voltage regulator can do it too, by energizing the alternator. But since that's disconnected it's out of the loop.
What about that Black wire on the alternator? Was it disconnected too?
The power cable from the new voltage regulator to the fuse box is disconnected. The connector is about 6 inches form the Volt reg.
After starting I have 4.2 volts from the disconnected neg cable to the neg post.....
Good test, but I'm not sure what it indicates. Someone should know though.
With the power connector unplugged and it started.
Which power connector?
When I connect the power cable the rpms drop slightly with the cable still on the battery.
This would indicate to me that the alternator is charging and that's what's drawing the engine speed down slightly.
It runs without being hooked to the battery. Indicating part of the alternator is good.
Yes, if the engine stays running with the battery disconnected the alternator is keeping it running. But this is possible even with a bad alternator. The internal diodes failing (the usual cause of a draining battery) don't keep the alternator from charging when it's spinning.
Since I replaced the Voltage Reg, perhaps it is the solenoid or Alternator. How would I check?
A new part does not guarantee the part is good. Remember that and live by those words in this day and age of crappy parts.
But having disconnected it and still having the drain, you've indicated that the regulator is not part of the problem.
The starter relay is not the problem. Can't be since the other small wires were disconnected too. Correct?
If the battery is draining quickly (anywhere from 2hrs to 5hrs usually) it's usually one of two things. A dying battery, or a faulty alternator. Since the battery does not die when it's disconnected (I think I remember you saying that, but I'll have to go re-read the thread to be sure) then it's most likely the alternator, like we were talking about before.
But now the kicker. Didn't you disconnect the alternator's main Black wire when you disconnected that 3-wire connector in your first pic? If so, and the battery is still draining, it can't be the alternator because it's disconnected from the system.
If it's connected, disconnect it and try the overnight drain test.
So to test, you need to disconnect the alternator completely from the system and that will tell you. If it drains the battery overnight all the time with it connected, and does not with it disconnected, then you've found your issue.
Paul