Air supplied to the engine passes through venturi 1. Owing to the increase in air velocity, the pressure in the venturi drops sharply. At this, fuel from chamber 2 is drawn up through gauged hole a in a tube located along the axis of the venturi. By means of float 3, a constant level of fuel is maintained in chamber 2. As the level drops, float 3 descends, turning about fixed axis A. At this, the other end of lever 4 is raised, opening valve 5 and thereby increasing the amount of fuel supplied to the float chamber. When the level rises, valve 5 is closed, stopping the supply of fuel to the chamber.
$3785$SHP,FD$