Autolite Motorcraft 2100. Rebuilt twice. 3rd needle and seat. After the car sits for 10 minutes you see the fuel draining from the clear gas filter. Pop the top of the air cleaner, you can see vapor from the throat. Fuel is draining down the gullet. OK, so we rebuilt this carb now twice. Shall I continue to lower the float? Try a 4th needle and seat? What gives?