A fuel supply unit (1) is provided e.g. a carburetor or a low pressure injection system of an internal combustion engine. The fuel supply unit (1) includes a main air passage (3), which has a throttle valve (8, 9) mounted therein and the throttle valve (8, 9) includes a throttle shaft (8) extending between two to one another opposite located shaft sides (6, 7). A control module (2) for the fuel supply (2) is mounted to one (7) of the shaft sides (6, 7), which control module (2) includes throttle position detecting means (30; 300) for monitoring the position of the throttle valve (8, 9), and fuel valve means (60) for controlling the fuel supply to the main air passage (3). Also, an ignition system is provided which is able to control the ignition timing with respect to status of the at least one of the means (30; 300, 40, 60, 100) in the control module (2) in order to at least control the idle speed of the engine. The ignition system further being arranged to power at least one of the means (30; 300, 40, 60, 100) of the control module (2).