A fuel supply system for a reciprocating-piston engine includes a storage tank; a wall of the storage tank defining a first aperture and a second aperture therethrough; a first fuel injector fluidly coupled with the first aperture of the storage tank via a pressure control module and a first fuel injector supply conduit; a pump fluidly coupled with the second aperture of the storage tank; and a second fuel injector fluidly coupled with an outlet port of the pump via a second fuel injector supply conduit. The pressure control module is configured to maintain a pressure in the first fuel injector supply conduit within a pressure range that includes a pressure value that is less than a pressure inside the storage tank. The pump is configured to maintain a pressure inside the second fuel injector supply conduit that is greater than the pressure inside the first fuel injector supply conduit.