Hi John
When the dial on the front is turned to "off" the lever inside the cover should close the air vent and pull up on the float pin to stop gas from entering the carburator. If it still leaks, you can try lapping the inlet needle to it’s carburator seat. The other solution would be to shut off the fuel at the fuel line shut off and run the carburetor dry.
This would require you fog the motor with fogging oil for storage. When stored, the speed control should be in the STOP position to ensure the air shutter on the side of the cylinders is closed to keep moisture away from the piston rings.
I hope this helps
