Abstract: An engine fuel system includes a fuel pump located within an upright reserve fuel container located in a fuel tank. Fuel is admitted to the inlet chamber of the pump through separate poppet valves associated with the fuel tank and the reserve fuel container. The container is a sealed construction that isolates the fuel in the container from the fuel in the tank. The poppet valve leading from the tank to the pump is operated by a float that is responsive to the fuel level in the tank. At low tank fuel levels (empty or near empty), the float-operated poppet valve is closed. The two valves are interconnected by a lost motion connection such that the poppet valve associated with the reserve container is openable by pressures generated in the return fuel line, or by suction forces generated by the fuel pump. The reserve container is maintained in a filled condition ready for supplying fuel to the pump when the fuel tank is in a near empty condition.