Arranged in the fuel tank is a reservoir into which fuel is pumped by a jet pump connected to a return line from the internal combustion engine. The jet pump has a jet nozzle which is arranged in a holder formed on the reservoir. Between its inlet opening and the propulsion-nozzle opening, the jet nozzle has a bypass opening which is connected to a stub projecting into the reservoir. At its end, the stub is provided with a seat which can be closed by a closing element. Arranged in the reservoir is a leaf spring which is fixed at one end and which presses the closing element onto the seat. Together with the closing element, the bypass opening forms a bypass valve which allows fuel to flow out of the jet nozzle if a certain pressure is exceeded.