Membrane carburetor

A membrane carburetor for an internal combustion engine in a portable handheld work apparatus including a motor-driven chain saw, cutoff machine and brushcutter, the engine having a fuel tank and the membrane carburetor comprising:

• a carburetor housing defining an intake channel communicating with the engine and through which a stream of combustion air flowing in an intake flow direction is drawn by suction when the engine is operating;
• said carburetor housing defining an interior space;
• a control membrane mounted in said interior space so as to define a control chamber therein bounded by said control membrane;
• a fuel supply line connecting said fuel tank to said control chamber;
• a control valve mounted in said fuel supply line and being actuable to control the inflow of fuel to said control chamber;
• said control membrane being operatively connected to said control valve for actuating said control valve to clear said fuel supply line in response to a deflection of said control membrane whereby fuel flows into said control chamber;
• at least one fuel nozzle;
• an ancillary chamber disposed in said carburetor housing;
• a fuel path connecting said control chamber to said fuel tank;
• a purge pump mounted in said fuel path;
• said control chamber being connected to said intake channel via said ancillary chamber and said fuel nozzle;
• said fuel path including a segment thereof between said control chamber and said purge pump;
• and,
• said fuel path being so configured that said segment thereof passes through said ancillary chamber.