Tony,
Sounds like your float might be not closing the needle into the seat. Remove the bowls and check to see if the float will close. Also a float can become defective and stop "floating". Remove it and place it a small container of fuel to make sure it still floats. Lastly the tang that that closes the needle can bent to adjust the fuel level in the bowl. With the carb inverted measure from the top of the float to where the fuel bowl would sit. Should be 17mm.
