A regulated flow of fuel under pressure from the fuel pump enters the carburetor through the fuel inlet needle valve. The float rises and falls with the fuel level in the float chamber. The float lever, which is hinged to the stationary float shaft, controls the fuel inlet needle valve, permitting only enough fuel to pass through the valve to replace that being used. This maintains a constant level of fuel in the float chamber.
Economical operation of the carburetor depends to a large extent on the proper fuel level in the bowl. The float level can be set very close, when the air horn is removed, by gauging the distance between the bottom of the float and the flange surface of the air horn. Holding the air horn, less gasket, upside down and with the float in the closed position, measure the distance from the flange surface of the air horn to what would normally be the bottom side of the float (not the soldered seam). The correct distance should measure 1 1/4”. To correct the float setting, the float lever arm should be bent up or down to bring the float within the established limites and thus correct the fuel level for best operation. Pushing the float toward the float chamber cover raises the level, pushing away from the cover lowers the level.