A fuel supply system for an internal combustion engine having inlet porting and a fuel supply passage with valve means therein, the cross-sectional area lying within the outside passage walls being greater in the region of the valve means than in a region upstream of the valve means. An element is disposed in the passage tending to equalize the velocity of the fuel flow through the supply passage in different regions thereof, and means are also provided in connection of a fuel reservoir or vessel to the fuel supply passage or channel in the region of and through said element.