The carbs use two different seats I believe. One for a fuel pump has a smaller hole.
Needle and Seat kit with fuel pump-KOH1252104
Needle and Seat kit without fuel pump-KOH1252103
Make sure the line isn't split.
Check the bowl real close to make sure it doesn't have a pin hole. Wipe it off, dry with air and open fuel valve to see exactly where fuel is coming from.
Check the fuel pressure to make sure it is not 100psi. I do not know what the norm is but 5psi is what comes to mind. You can rent a tester from Autozone.
I would remove the carb. Remove the bowl. Make sure gasket isn't crunched. Some carbs I have rebuilt had a washer inside between carb and bowl. I usually delete it because it doesn't look right. Someone should correct me if I am wrong....
If the vent is clogged, the float will not work correctly.
This is how I test troublesome carbs:
Now, remove float. Shake it. If it has liquid in it, replace it. Check needle. If the needle is solid aluminum, there should be a rubber gasket in the seat(bushing). If the needle has a rubber tip, there should not be a rubber gasket in the seat. Some kits come with both needles and extra parts. Put float back in place. Do not install carb or bowl. Connect fuel line. Turn carb upside down with float upwards. Dry off needle and seat area with air. Open fuel supply. See if it gets wet. Kinda hard to do if you need the engine cranking to get fuel. You might need to connect before the pump for testing. If it gets wet around the needle, either you need a new seat(bushing mentioned in the part numbers above) or the carb has a hairline crack.