A device for intimately intermixing a liquid fuel, air, and preferably also a metered proportion of water, for delivery to an internal combustion engine or other fuel burning mechanism, the device including a rotor to which the fuel and water are delivered for centrifugal discharge radially outwardly in finely divided mist form, with the rotor preferably carrying a large number of minute fibers projecting radially outwardly and along which the liquids flow in a manner subdividing the liquids into minute droplets. The rate of delivery of the fuel and water is regulated in accordance with the rate of flow of air through the device, and by a control structure actuable by the air.