A device for mounting in a fuel dispensing hose (11) that has a flexible inner tube (14) defining the fuel conduit, and a tubular outer sleeve (13) that defines with the inner tube an annular vapor return passage (15). The device includes an aspirating block (20) adapted for serial connection with the inner tube (14) within the outer sleeve (13). The section comprises a cylindrical block that is connected in series with ends of the inner tube and defines a venturi (22, 59) or jet pump forming part of the fuel conduit. The block also includes bypass passages (54) for fuel to bypass the venturi (22, 59) and to increase the fuel flow through the block. The aspirating block also has radial aspirator ports (35) which communicate between the venturi throat (22, 59) or jet pump and the annular vapor return passage (15). Each radial aspirating port (35) includes a check (44) valve to permit only one-way fuel flow from the vapor passage (15) to the fuel conduit.