Abstract: The invention is directed to a start-assist device on a membrane carburetor of an internal combustion engine in a motor-driven chain saw which is to be started manually. The carburetor includes a control chamber delimited by a control membrane. The control chamber is supplied with fuel from a fuel tank via control valve. The control valve is opened by the control membrane when the underpressure builds up in the control chamber so that fuel flows in. This fuel is supplied to the air-inducting intake channel via an idle nozzle and a main nozzle. The fuel feed system further has an outlet for vapor bubbles or the like. A pump which is driven indirectly from the start operation is provided and has a suction connection connected to the outlet in order to ensure, with few start attempts, a reliable start of the engine independently of the temperature state of the engine and other influences.