An emulsion tube for a carburetor is formed with a porous wall surrounding an inner passage, wherein air travels about one side of the wall and fuel travels about the opposite side, with air being supplied through the pores to aerate the fuel (with the aerated fuel then being expelled into a venturi wherein engine intake air is traveling to further mix the fuel with the intake air therein). The emulsion tube can beneficially provide a high degree of fuel/air mixing across the entire range of intake airstream flow rates at which an engine may operate. The porosity of the emulsion tube can also be tailored to provide the desired fuel/air ratio(s) across the engine's operational range of intake airstream flow rates.