Float Circuit

Fuel in the carburetor must be maintained at a certain level under all operating conditions; this is the function of the float circuit. The needed fuel level is maintained by the float. When its attached lever forces the needle valve closed, the flow of fuel from the pump is stopped. As soon as fuel is discharged from the float bowl, the float drops. The needle valve opens and fuel flows into the bowl again. In this way, the fuel is level to the opening of the main discharge nozzle. The float level must be set with a high degree of accuracy. If the level is too low, not enough fuel will be supplied to the system and the engine will stall on turns; if the level is too high, too much fuel will flow from the nozzle.