Just a guess....But is it possible that there was a little bit of water in
the bottom of the fuel tank which was sucked into the carburetor? This
would explain the drops in RPM as the water filled the bottom of the carb
float bowl until the water level raised enough to stop the genset from
running. You would still see liquids in the fuel lines like you saw. See
if there is an easy way to drain the carbureator bowl and catch the contents
in a clear jar. Water will sink to the bottom.

The low voltage you are reading may be normal until the unit is up to
speed...

Good Luck!

Last week, it ran down in rpms a couple of times, and then died. All
efforts to restart have failed. I was low on fuel in the supply tank,
and figured that was the problem.

I have cracked the solenoid from the carb
housing, and have fuel running out, so I "don't" think I have a fuel
pump problem.

I am not developing A/C voltage, though. IT's like 10 volts on the
panel meter, or something trivial during the start.

Would the lack of the battery charger output from the A/C side be
causing this symptom?

Any other ideas?