Abstract: A device for reducing noxious emissions from carburetor engines of the internal combustion type, the body of which comprises at least one main passage designed for feeding a fuel-air mixture to the engine cylinders and has an emulsion passage. The main passage accommodates a throttle valve which divides it into an upstream throttle space and a downstream throttle space, as viewed in the direction of the fuel-air mixture flow. The emulsion passage communicates with the upstream throttle space substantially in the area where the throttle valve upper edge locates when the throttle valve is in the closed position and also communicates further, as viewed in the direction of the emulsion flow, via an adjustable throttle element with a chamber which communicates via an air passage with the upstream throttle space and via a passage with the downstream throttle space. The chamber accommodates a movable element adapted to move coaxially with the passage for the purpose of closing same.