Diagnostic questions

Hi guys, I've been gone a while but I just picked this group up again.

One day several months ago I loaned my bug to my daughter for the day
and something happened when she was out and about with it and almost
didn't get it home. I'm having trouble narrowing down what's wrong.
When the problem started the weather was crappy and I didn't have the
garage space to roll it in so I put it off until things got warm. Then
I was busy all summer and I'm just getting back to it. Along the way I
worked on it a little here and there but not enough to really get to the
bottom of the problem.

This engine has about 30k miles on it. I rebuilt it and had Dan Hall's
machine shop in Portland do all the machine work. The compression is
good and the oil pressure hasn't changed since the engine was first put
into service. BTW, this is the engine that I used to refer to the
perpetual project. It spent over 10 years in my bedroom closet waiting
for me to get around to finishing it...

The engine cuts out a low RPM and gets worse as it warms up. By the
time it should be warmed up enough to idle, it's running worse and I
can't get to the back of the car to tinker with it. BTW the power is OK
until it warms up then it hard to keep it running. Judging by the oil
pressure, it never gets to fully warmed up before it's running like crap.

My first thought was the points and condenser were likely bad. I had
the money so I put in an electronic ignition kit. It ran the same and I
thought maybe it was fuel starving. Draining the gas gave an
unimpressive flow rate so I pulled the tank and cleaned the screen. The
screen was about half blocked so I figured I found the problem. Since I
was in there, I installed an electric fuel pump and put a new fuel
filter between the pump and tank. Still no change.

I've also been going over the electrical connections. I've been
cleaning them or replacing them as required and packing them with
dielectric grease. I've fixed all sorts of little problems that have
had no effect on the problem.

There is a bit of soft soot inside the end of the exhaust pipe and while
I don't see any black smoke, it does smell a little rich. right now I'm
thinking it's either the carb or the coil is weak. Any suggestions?

Tony