Abstract: A marine propulsion unit is disclosed which has an exteriorly accessible clean-out capability. The unit has an impeller housing located outside of the transom of a marine craft in which the unit is installed, which impeller housing has a separable portion that permits access to the main passage including the impeller when separated. The design also permits insertion of a hose connected fitting for backflushing the cooling system of the power head of the unit.

Abstract: An exhaust system for a marine jet pump with an internal combustion power head includes a muffler having a muffler inlet in fluid communication with the power head to receive exhaust gases therefrom, and a muffler outlet for emitting the exhaust gases, the muffler further including an exhaust high rise portion being vertically displaced from the inlet and the outlet to prevent the entry into the muffler inlet of water passing into the interior through the muffler outlet.

Abstract: A system for mounting a jet propulsion unit to a watercraft having a hull with a mounting opening, the jet propulsion unit including a power head and a jet pump housing secured to the power head, the mounting system including a power transmission portion disposed on the jet pump housing, and a mounting apparatus associated with the transmission portion for mounting the propulsion unit directly to the hull.

Abstract: A marine propulsion device comprising an upper housing which has a lower surface and which is adapted to be mounted on the transom of a boat for pivotal movement relative thereto, a lower housing having an upper surface mating with the lower surface, a propeller shaft rotatably supported by the lower housing, and an arrangement for reducing fretting between the lower surface and the upper surface.

Abstract: An internal combustion engine comprising an engine block, a spark control member movably mounted on the engine block, means for controlling the spark timing of the engine in response to movement of the spark control member, a first actuating member movably mounted on the engine block, and means for adjustably connecting the first actuating member to the spark control member for common movement therewith.

Abstract: An internal combustion engine comprising an engine block including a cylinder and a combustion air passage for supplying combustion air to the cylinder, an air silencer communicating with the combustion air passage, and an elastic connector for securing the air silencer to the engine block.

Abstract: An outboard motor comprising a lower unit, a propeller shaft rotatably supported by the lower unit and adapted to support a propeller, and an internal combustion engine supported by the lower unit and drivingly connected to the propeller shaft, the internal combustion engine including an engine block defining at least one cylinder and having a lifting hook integrally formed on the engine block.

Abstract: Disclosed herein is an inner exhaust gas housing adapted to be located within a drive shaft housing of an outboard motor, which inner exhaust gas housing integrally includes an open upper end, a first exhaust passage extending downwardly from the upper end, a second exhaust passage extending downwardly from the upper end, an expression chamber adjacent the upper end, a first passage communicating between the first and second exhaust passages and the expansion chamber, and a second passage communicating with the expansion chamber and with the atmosphere exterior to the inner exhaust gas housing.