Abstract: A device for adjusting the degree of opening of the throttle valve of a carburetor comprising a cam pivotally mounted on a pivot. The cam is actuated by a wax valve and rotated in accordance with an increase in the temperature of the cooling water of the engine. The cam has a cam face which is engageable with a lever connected to the throttle valve for retaining the throttle valve at a predetermined fast idling degree during engine warm-up. An auxiliary lever is pivotally mounted on the pivot. The auxiliary lever has an outer circumferential face which is engageable with the lever of the throttle valve for retaining the throttle valve at the predetermined fast idling degree after completion of engine warm-up.

Abstract: A variable venturi type carburetor includes a suction chamber, a suction piston moveable into and out of the chamber, a metering needle attached to the head portion of the suction piston, the needle being faced by a metering jet. The carburetor also includes a throttle valve. The head portion confronts the venturi section at the upstream side of the throttle valve. The head portion is obliquely cut or shaped at one side, which faces the throttle valve, and desirably is so positioned relative to the throttle valve that at least a portion of the throttle valve pivots during opening movement within space vacated by the obliquely cut or shaped piston portion as the piston moves in an opening direction.

Abstract: Disclosed is a variable venturi type carburetor which is provided with a suction piston movable in a direction perpendicular to an air flow, in accordance with changes in the air flow, so as to vary the area of a venturi opening formed between the bottom end of the suction piston and a wall of the carburetor body facing the bottom end of the suction piston, for maintaining the speed of the air flow passing through the venturi opening substantially constant. The suction piston has a hole formed therein communicating the venturi opening with a suction chamber in which the suction piston is moved. The carburetor has a spring for urging the suction piston, but does not have any oil damper within the suction chamber. The shape of the venturi opening is so arranged that the increase of the area of the venturi opening in accordance with the displacement of the suction piston is gradually increased.

Abstract: Disclosed is a variable venturi type carburetor comprising a movable suction piston which changes the cross-sectional area of a venturi portion of an intake passage in response to the amount of air flowing therethrough. The suction piston has a needle entering into a stationary jet. The needle and the jet define an annular opening through which the fuel is injected into the venturi portion. The jet is connected to a fuel reservoir via a fuel supply passage. On the bottom face of the suction piston and on the inner wall of the venturi portion, members for magnetically attracting each other are mounted, respectively.