<VV> Drippy Carbs?

[grant young]

I have been asked to help trouble shoot a carb problem, but am somewhat
baffled by it. These are semi-fresh rebuilds on a just completely rebuilt
140 engine. The car starts, idles, and drives okay and is getting 25 mpg.
But, it is hard to start when warm. This is probably due to the problem of
all four carbs dripping fuel into the engine after shut down. The owner had
a new fuel pump, but replaced it with the old one and the problem
continues. If it were a single carb, I would guess that there was a bad
float or loose/dirty inlet seat. But all four??? Input appreciated.
Thanks,
The (baffled) carbmeister