gcb

Yuu,
Might you have put the gasket in the wrong place? It should go next to the metal crankcase.

Re: the cast crankcase. I do not have one of these but if I remember correctly, aluminum crank cases were used in a production model. They looked like the zinc ones except the zinc was darker.

George

Edit: Another thought...might your engine have been one made before the plastic was used? Previously, the reed was retained with a spring clip. Some rebuild kits had parts for both.