Abstract: An air-fuel ratio control device for an internal combustion engine equipped with a plurality of variable venturi type carburetors each having a slow system, in which the flow rate of air supplied to the slow systems of the carburetors is controlled depending on the engine operation parameters including, for example, the temperature of intake air, temperature of engine oil and atmospheric pressure to improve the rate of atomization of fuel, thereby improving the idling performance of the engine and therefore improving the fuel consumption of the engine.

Abstract: A throttle valve linkage for use with a multi-carburetor assembly comprising a pair of carburetors has first and second levers secured respectively to the throttle shafts of the first and second carburetors, first and second link members respectively connected at one ends to the free ends of the first and second levers. The other ends of the first and second link members are pivotally connected by a common pivot pin which is slidably movable in a guide channel. The rotation of the first carburetor throttle shaft is transmitted by the linkage to the second carburetor throttle shaft so that the latter is rotated in a direction opposite to the direction of rotation of the first carburetor throttle shaft.

Abstract: A slow fuel controlling device for a carburetor in which fuel metered by a slow jet is mixed with air induced through a slow air bleed in the form of counter flows and the mixture thus formed is supplied into a portion of the intake passage near a throttle valve, and the diameter of the fuel feed passage is selected to substantially fill said passage with fuel by utilizing capillary action.