Abstract: A diaphragm carburetor with a fuel metering chamber designed for easy restart when hot which includes a separate escape chamber connected to the metering chamber having a second diaphragm controlled exhaust valve. The second diaphragm is subject to positive crankcase pressure during engine operation to maintain the exhaust valve closed. When the engine is stopped, the exhaust valve is opened by a spring and fuel in the metering chamber will move into the escape chamber and out of the carburetor rather than be forced into the fuel mixing passage and venturi of the carburetor.

Abstract: A diaphragm carburetor for small internal combustion engines of generally standard construction but improved features for facilitating hot starting due to engine heat or environmental heat which transmits to the carburetor. An automatic or manual relief passage from the diaphragm chamber relieves pressure on fuel due to heat conductors so that a rich fuel charge will not be forced into the engine but will release to atmosphere, thus permitting a normal fuel mixture to be directed to the fuel mixing passage upon a restart of the engine.