Carb Drip

Or the wrong carb kit. This happened to me several years ago. Mine was a AFB.
The new seats in my kit were a bit taller than those removed from the carb. Took me quite a while to notice this slight difference, finger out where the fault was. I could not get the bowl level / needle seat operation to set up right.
I have to assume the same or worse "head scratcher" would happen when changed from tall to short seats. Taller would not open to let fuel in, so shorter would never fully close?
If still you have the original parts that were removed, compare the seat height closely. I can testify that they aren't all the same. Good luck with it.