Any 2 stroke experts out there

If you have fuel tank shut off valve use it, if not buy an inline valve. Sounds like raw fuel draining from the carburetor into the crankcase area where it sits until the engine is started. The fuel not being atomized will be force out during the exhaust stroke. If the muffler has an inner baffle take it out and shine it up on the wire wheel.....check float...check needle valve and seat.