Fuel evaporating out of the carb is normal, they all do it. Once the carb is dry, the float opens the needle and seat. The fuel now evaporates out of the line and filter by way of the seat opening. It continues down the line to the pumps, where the check valve should seal off the main fuel line.
Adding a 1/4 turn shut off at the carburetor inlet will minimize cranking, but then you need to be under the hood overtime you go to start it.
Electric primmer pump is the quickest and easiest fix.
