You don't have to lay on the driveway to get the generator out -
you can do it all over the fender. When you put it back in be sure
and tighten all the bolts, especially the bottom ones, front and back.
The aluminum ends of the generator really suffer if you don't.

Sounds to me like you might need a new set of brushes in your
generator if it works well sometimes and not at others.
They are pretty easy to install and you don't have to take the
generator apart - just remove the band around it and you can get
to the brushes. Anyplace that overhauls generators should have brushes
that will fit. Take the old brushes with you. Shouldn't be more than
a few $.

Clean the commutator while you are in there. Emery cloth or a strip of
wetordry usually will do it OK.

Be sure the battery is disconnected while you are working on the system.

Connection to power with the system not working can damage your regulator.
--
George Downs Bartlesville, Oklahoma