Abstract: A watercraft includes a trim control and a fuel injection system. The fuel injection system is designed so that the discharge portion of the supply line from the low pressure pump to the high pressure pump extends in a generally downward direction regardless of the trim adjusted condition of the watercraft. In a like manner, the fuel rail which has a high pressure inlet at one end and a return line at the other end is disposed so that the return line is disposed vertically above the inlet under all trim adjusted conditions for automatic vapor purging.

Abstract: A personal watercraft includes a catalytic exhaust system in order to reduce discharge of pollutants. The exhaust system includes an exhaust passage and a catalyzer that is located within an expansion chamber of the exhaust passage. A water jacket is provided adjacent the expansion chamber and a portion of water from the water jacket merges with the exhaust pipe at a merge point downstream from the catalyzer. The distance within the exhaust passage between an exhaust port of a combustion chamber and the front of the catalyzer and from the rear of the catalyzer to the coolant-exhaust merge point is such that a pressure wave from the combustion chamber reflects back from downstream of the catalyzer carries an exhaust/water mixture from the merge point upstream across the catalyst, thereby cooling the catalyzer. Also, an insertion port disposed in the exhaust system upstream of the catalyzer injects cooling water into the exhaust system, thus cooling the exhaust gases and the catalyzer.

Abstract: A marine engine is constructed having an improved component layout so as to reduce the size of the engine even when multiple fuel injectors are employed per cylinder. In one mode, this advantage is accomplished while shielding the fuel injectors from water that may enter through an access opening above the engine. The fuel injectors are also desirably arranged to reduce thermal effects on the fuel injectors by remotely positioning the fuel injectors relative to the engine's exhaust system. In one form, the fuel injectors are mounted on a lower surface of an inclined cylinder and the exhaust pipe is connected to an upper surface of the cylinder for these purposes.

Abstract: Several embodiments of personal watercraft having direct injected, internal combustion engines that employ mechanically driven high pressure pumps. In each embodiment, the high pressure pump is driven off the engine crankshaft in such a relationship to the magneto generator or alternator drive for the engine to provide a compact yet serviceable construction.

Abstract: A marine engine is constructed having an improved component layout so as to reduce the risk of water contact with an oxygen sensor of the engine. This advantage is accomplished by providing a collection chamber that promotes drainage of any water that may enter into the chamber through an exhaust system. In one form, the oxygen sensor chamber has a lower wall and a passage thereof, both slanted downward toward the corresponding cylinder of the engine. The oxygen sensor may be shielded by a portion of the engine (e.g., by the induction system or the cylinder block) or by a portion of the corresponding exhaust system. In another variation, the oxygen sensor can be located for easily access in order to facilitate service and replacement.

Abstract: In accordance with the present invention, there is provided a control for an engine of a watercraft. The watercraft is preferably of the personal variety, and includes a water propulsion device which is driven by an output shaft of the engine. The engine has at least one combustion chamber, an intake system providing air to the combustion chamber, a fuel system providing fuel to the combustion chamber for combustion therein, and an ignition system including at least one ignition element associated with the combustion chamber. The watercraft engine control is of the type which does not include a main switch, but is arranged to turn on electrical systems of the engine when the engine is started and shut them off when the engine is stopped. The control includes a lanyard switch having first and second positions. In a first position the lanyard switch permits power to flow to the ignition element and the electrically-powered engine features, such as a fuel delivery mechanism.

Abstract: A breather arrangement for an engine powering a water propulsion device of a watercraft having a hull defining an engine compartment in which the engine is positioned is disclosed. The engine has a body defining at least one combustion chamber and has an output shaft arranged to drive the water propulsion device. The engine includes an intake system through which air is supplied to the combustion chamber, the intake system including an air intake pipe extending from the body of the engine to an air box having a top surface and a bottom surface and an air inlet leading into an interior air space. The breather includes a passage leading from the engine body to an opening in fluid communication with the intake system, the opening positioned at other than the top or bottom surface of the air box.

Abstract: An arrangement for at least one fuel injector associated with a fuel injection system of an engine powering a water propulsion device of a watercraft is disclosed. The watercraft has a hull defining an engine compartment and includes a water propulsion device. An internal combustion engine has a cylinder head connected to a top end of a cylinder block and cooperating with the cylinder block to define at least one combustion chamber. The engine is positioned in the engine compartment and has an output shaft arranged to power the water propulsion device. At least one air duct provides air through the hull into the engine compartment, the duct leading from the hull to an outlet in the engine compartment. The engine has an intake system for providing air to the combustion chamber and a fuel system for providing fuel to the combustion chamber, the fuel system including at least one fuel injector extending from the cylinder head positioned above the air duct outlet and shielded by the engine from water.

Abstract: An engine control for an engine powering a watercraft is disclosed. The engine has a body defining at least two combustion chambers. An air supply system supplies air to the combustion chambers, the air supply system including a throttle control for controlling the flow rate of air to the engine, the throttle control moveable between an open and a closed position. A fuel supply system supplies fuel to the combustion chambers. At least one ignition element ignites the air and fuel supplied to the combustion chambers. At least one exhaust passage leads from the combustion chamber to a point exterior to the body through which exhaust may pass. Exhaust control means are provided for controlling the timing of the flow of exhaust through the passage.

Abstract: A number of embodiments of personal watercraft having catalytic exhaust systems for treating and purifying the exhaust gases. In all of the embodiments, the catalyst is positioned and disposed so as to be protected from water. In addition, arrangements are provided for cooling the catalyst, for circulating ventilating air across it, for isolating it from other components such as the fuel tank, and for permitting its flushing with fresh water after operating in a salt water environment.

Abstract: A personal watercraft includes a catalytic exhaust system in order to reduce discharge of pollutants. A catalyzer of the exhaust system is located within an expansion chamber. The expansion chamber, as well as the internal combustion engine of the personal watercraft, are enclosed within a hull. The watercraft hull desirably includes an access opening located near the catalyzer. The access opening is of a size sufficient to allow at least the catalyzer to be removed from the hull of the personal watercraft for servicing or cleaning.

Abstract: An arrangement of an exhaust gas collection port within an exhaust system of a small watercraft increases the accuracy of an associated probe's readings. The port is located upstream of a point where cooling water is introduced into the exhaust system for silencing purposes. As a result, the ingress and egress of exhaust gases flow into and out of the port is generally unimpeded by the cooling water. The tendency of water to enter and clog the port is also reduced. The precision of the associated exhaust probe measurements consequently is greatly increased.

Abstract: An improved fuel delivery and injection system for a small watercraft engine reduces the heat effects within an enclosed engine compartment upon various components of the engine and upon the fuel within the fuel system. The fuel system integrates a fuel pump within a fuel tank at a location which minimizes the effects of watercraft leaning. The inlet of the fuel pump desirably corresponds, in the lateral direction, with a position of an inlet to the jet pump unit. In this position, the pump is less likely to draw air as the watercraft maneuvers. The fuel lines also are arranged within the engine to minimize the effect of engine heat produced by the exhaust system on the fuel delivery lines. The arrangement of the fuel pump and fuel delivery lines consequently improves the consistency of the fuel/air ratio within the fuel charge produced by the engine as less air and vapor delivered to the fuel injectors.

Abstract: A small watercraft includes an improved exhaust system that reduces the width of the engine and associated exhaust pipes. The watercraft includes a hull having a length in a longitudinal direction, a width in a lateral direction, and a longitudinal center line. A multi-cylinder engine is carried by the hull. The engine includes an exhaust system with multiple exhaust inlet ends and at least one downstream end. The exhaust inlet ends communicate with the respective cylinders of the engine. A flow axis through each inlet end extends in a direction generally parallel to the longitudinal axis of the hull. As a result, the exhaust system does not significantly protrude in a lateral direction beyond the sides of the engine. The hull consequently has a smaller width than the prior watercrafts which improves it maneuverability.

Abstract: An improved catalytic exhaust system for a watercraft provides two stage treatment of exhaust gases before expulsion from the watercraft. The catalytic exhaust system also is configured to minimize the restriction the catalysts pose to exhaust gas flow through the exhaust system so as to reduce engine back pressure and improve engine performance. A catalytic device of the exhaust system includes a pre catalyst and a main catalyst positioned downstream from the pre catalyst. The pre catalyst can take the from of a catalytic material coating along a portion of the exhaust flow path and the main catalyst can be a catalyst bed. The exhaust gas flow path through the exhaust system also smoothly tapers into and out of the main catalyst so as to reduce the degree of flow resistance through the main catalyst.

Abstract: A watercraft engine control system for controlling the temperature in the exhaust system to protect against potentially dangerous situations. If the exhaust temperature is sensed to be unduly high, a protective action is initiated. This protective action reduced in the flow of unburned fuel to the exhaust system either stopping of the engine or reducing its speed below idle. The protection action may be initiated either immediately or if the situation occurs for more than a predetermined time period.

Abstract: An exhaust pipe cooling system is provided for a small watercraft, such as a personal watercraft, to regulate the temperature of a catalyzer of an associated exhaust system. The cooling system supplies fresh water to a water jacket which surrounds the catalyzer in a manner independent of an engine cooling system. A control valve also can regulate the flow rate of water through the cooling system to adjust the temperature of the catalyzer to fall within a desired range of operating temperatures.

Abstract: An oil supply system for a watercraft which is powered by an internal combustion engine driving a water propulsion device is disclosed. The system delivers oil to the engine in accordance with a first rate of increase as engine speed increases in a first low engine speed range, and in accordance with a second higher rate of increase as engine speed increases in a second engine speed range higher than the first engine speed range. The lower rate of oil delivery in the first engine speed range is selected to prevent fouling of a catalyst of the engine.

Abstract: A number of embodiments of a personal watercraft are disclosed which have a catalytic exhaust system for treating and purifying exhaust gases. In all of the embodiments, the catalyst is positioned and disposed so as to be protected from water. In addition, arrangements are provided for cooling the catalyst, for discharging at least a portion of coolant upstream of the catalyst, for circulating ventilating air across it, for isolating it from other components such as the fuel tank, and for permitting its flushing with fresh water after operating in a salt water environment.

Abstract: A number of exhaust systems for watercraft propelled by a propulsion unit contained within a tunnel formed in the underside of the hull. This tunnel has an opening through the side of the hull and exhaust gases are delivered to the tunnel from the engine through an exhaust system having an exhaust opening communicating with the tunnel. Various flow controlling arrangements are provided for controlling the flow through one or all of the openings so as to assist in exhaust silencing without significantly increasing back pressure.