Abstract: Enriching device for carburettors of internal combustion engines, which comprises an aeration gaged orifice located at the upper portion of the float tank of the carburettor, a fuel gaged orifice communicating with the bottom of said fuel tank, an air/fuel mixture gaged orifice disposed in a passage interconnecting said aeration gaged orifice and said fuel gaged orifice, and delivering said mixture at the level of the carburettor venturi, and an additional gaged orifice opening into the main passage of the carburettor, wherein said additional gaged orifice is located at the end of a pipe section projecting to a predetermined extent into the main passage upstream of said venturi and slightly upstream of the closed position of the starter shutter, whereby said additional gaged orifice, according to the negative pressure discrepancy existing between its position and that of the mixture gaged orifice will regulate the richness of the air/fuel mixture by performing successively as an additional air inlet orifice f

Abstract: A carburettor having a slow running jet with a device for controlling the output of the slow running jet during deceleration. The device comprises an axially movable closure member inside the jet, its axial movements being dependent upon the magnitude of depression downstream of the normal butterfly throttle. The closure member has passage means allowing fuel flow to pass from a fuel inlet into the slow running jet and its movements are controlled by a diaphragm acted upon at one side by atmospheric pressure and on the other side by the pressure prevailing in the downstream side of the carburettor or the induction manifold.