Abstract: The invention refers to a downdraft carburetor for internal combustion engines, the choke tube cross-section being controlled by a choke tube valve whose movement is controlled as a function of the control pressure in the choke tube by means of a diaphragm and lever with spring support. The choke tube and the choke tube valve have the shape of a venturi nozzle. The control of the choke tube valve is so arranged that the closing moment increases with closing of the choke tube valve. A damping system is provided which consists of a diaphragm box placed in the float chamber of the carburetor and which is connected by means of levers with the levers controlling the choke tube valve.

Abstract: A drive mechanism for a fuel injection pump of an internal combustion engine, wherein a drive sprocket and an injection timer unit are arranged in a crankcase of the engine on a drive shaft connected to the camshaft of the fuel injection pump. The drive shaft is formed by a socket sleeve and is floatingly supported on the camshaft.