Gary wrote:

I know. I know: Get an alternator. OK, I'm seriously considering this
option. I'm looking
into what we can get that fits on our engine well (mounting holes, etc.)

BUT, I'd also like to know more about generators, how they work, how I can
test it
and the Voltage Regulator to isolate where the problem is. I've googled in
the past and
not found much.

Anyone know of good sites, books, or have the time to email with me about
how these
things work and how I can diagnose problems with them??

You seem to be going in 2 opposing directions. An old-style DC
generator & regulator is very easy to troubleshoot & any old auto
manual from the 6v car era will tell you all you need to know in 2
pages. For refitting it with an alternator, it is no different than
the thousands of shore vehicles that have been refitted, except it
needs a marinized alternator (i.e., tripple the price at retailg).
Since you already know a reubilder (?), I suggest you sidle up to him,
since he's seen it a hundred times & knows what common frame sizes fit
what. I also suggest you forget about being limited to only using the
original bracket & holes - almost no one does, and the typically
higher-producing alternator will merit a bracket appropriate to its
higher HP belt radial load, though some get fudged just fine with minor
mods or spacers. It is situational. Consider how wide the output
difference is btw your original generator & the proposed alternator in
amps, and use this as a rough guide to what you may or may not need for
a bracket or minor improvements to the one you have, and vs available
alternator frame configs. It is not complex, and you will waste $1000
worth of time trying to learn about it online.