Couple of thoughts;
When you go back through the carb, pay attention to the order of the gaskets and diaphragms. On the pump side its carb casting first, followed by the diaphragm and then the gasket and then the cover. For the metering side its casting then gasket then diaphragm, then cover. Notice that the order is reversed from side to side, and you might have the gaskets and diaphragms mixed up which will cause it to flood.
Also its possible that the carb has some varnish in it, the inlet needle may be having trouble sealing. How you fix this is to polish the seat where the inlet needle sits. Take the carb apart, removing the gaskets, diaphragms needle and lever etc and work over the sink. Water wont harm the carb. Go get a q-tip and cut it in half. Next, find some liquid silver polish (Wife, GF or Mom will have it) Hold the q-tip by the cotton part and insert the shaft into the area where the needle would ride. Turn the q-tip with your finger tips after dipping it in the polish. Do this a couple times. No force is necessary, all your doing is polishing. Wash all the polish out of the carb and let it dry. Install a new needle. Set the lever height and install the gaskets and diaphragms.
Varnish builds up in strange places. You can see the rubber inlet needle tip having trouble seating on an uneven surface.