Abstract: A vapour-separating fuel pump has a rotor which includes a pair of axially-aligned chambers having a first impeller arrangement between them. At least one of the chambers is frusto-conical and has its larger diameter adjacent the first impeller arrangement, the smaller end of this chamber forming the pump inlet. A tubular member extends axially within the other chamber and has an open end adjacent the impeller arrangement. The other end of the tubular member carries a further impeller arrangement. Liquid is discharged through a first outlet by the first impeller arrangement, and a vapour core within the tubular member is discharged through a second outlet by the further impeller arrangement.