Abstract: A marine propulsion system has a conduit (14) connected between a water cooled internal combustion engine (4) and a remote fuel tank (12). The conduit has a first passage (16) supplying fuel from the tank to the engine, a second passage (18) supplying cooling water from the engine towards the tank, and a third passage (22) returning water from the second passage back to the engine. The passages are in heat transfer relation to the conduit.

Abstract: A coupling assembly for connecting conduits conveying fuel under pressure, utilizes a pair of seals so as to define a chamber for the containment of excess pressurized fuel during the disengagement of the coupling members. A protective shield or flange is provided around the locking mechanism so as to prevent inadvertent contact with the release mechanism and accidential disengagement of the coupling members.

Abstract: A marine propulsion system includes a two cycle water cooled crankcase compression internal combustion engine (52) including a vapor separator (33), a remote fuel tank (60), and a fuel pump (62) in the tank for delivering fuel to the engine in response to crankcase pulse pressure. A combination conduit (64) between the fuel tank and the engine includes a first passage (66) communicating crankcase pulse pressure from the engine to the fuel pump in the tank, a second passage (70) supplying fuel from the pump in the tank to the engine, a third passage (74) returing fuel vapor from the vapor separator at the engine back to the tank, a fourth passage (78) supplying cooling water from the engine towards the tank, and a fifth passage (82) returning water from the fourth passage back to the engine.

Abstract: A marine propulsion system (2) with an outboard engine (4) has an oil-fuel mixing valve (16) within the engine cowl (6). A first crankcase pressure driven fuel pump (20) delivers fuel from a remote fuel tank (14) to the mixing valve, and a second crankcase pressure driven fuel pump (22) delivers mixed oil-fuel from the mixing valve to the engine. The arrangement provides adequate fuel pressure to overcome the added pressure drop across a reduced size mixing valve, all fitting within the engine cowl. The crankcase pressure pulses to the fuel pumps are 180.degree. out of phase such that when the first pump is pushing pressurized fuel to the inlet of the mixing valve, the second pump is pulling suctioned oil-fuel from the outlet of the mixing valve, to increase fuel pressure differential and enhance operation of the mixing valve.