After not being able to shut down the engine with the mixture control, Dee and Doug worked with Stratford to carefully remove the float bowl and, check the mixture spring/barrel assembly, and the needle valve assembly. Dee had purchased the new composite float and needle valve assembly and two bowl gaskets. Everything looked OK...no discrepancies we could see at all in the carburetor since Stratford had not loosened or removed anything else. We had the Marvel Schebler parts manual, service manual, and overhaul manual plus the float and needle valve assembly were shipped with multi-page instruction sheets printed in color!