A marine outboard engine includes an internal combustion engine including at least one fuel injector; a fuel vapor separator including: a separator body, a fuel reservoir defined by the separator body, and a first fuel pump fluidly connected between the fuel reservoir and the fuel injector; a fuel tank; and a second fuel pump fluidly connected between the fuel tank and the fuel vapor separator. The fuel vapor separator includes a heat exchanger disposed in the separator body. The heat exchanger includes at least one fuel channel defined by the heat exchanger body, the at least one fuel channel including: an inlet adapted for receiving fuel from the engine, and an outlet fluidly communicating with the fuel reservoir; and at least one coolant channel defined by the heat exchanger body, the at least one fuel channel and the at least one coolant channel being in thermal communication.