Abstract: A watercraft includes an improved engine control system that enhances the responsiveness of the watercraft and eases watercraft operation. The watercraft includes a propulsion device, such as a jet propulsion unit, and an engine that powers the propulsion device. The engine control system is configured to maintain or increase engine speed under certain operating conditions.

Abstract: A watercraft is provided with an engine. An exhaust system routes exhaust gases from the engine to an external location. The exhaust system has an exhaust conduit and a catalytic device affixed to the exhaust conduit. The catalytic device has a tubular member that extends in the exhaust conduit. Two intermediate members extend in the tubular member one after another along a flow direction of the exhaust gases. The tubular member supports each intermediate member. The catalytic device has two catalysts. Each intermediate member is affixed to the tubular member at one end thereof and supports each catalyst at another end thereof.

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 watercraft includes a monitoring and control system to sense the operational state of a catalytic device and a cooling system used with an exhaust system of the watercraft. The monitoring and control system receives temperature reading from an exhaust system temperature sensor. The sensor desirably is located in a portion of the exhaust system which the cooling system cools. The monitor and control system activates a first level warning indicators if the sensed temperature of the exhaust system exceeds a preselected first warning temperature. And if the sensed temperature exceeds a presented second warning temperature, the monitoring and control system reduces engine speed and eventually stops the engine. The monitor and control system also communicate with an exhaust gas temperature sensor which is located in the vicinity of a catalytic device of the exhaust system. If the sensed temperature is within a desired temperature range, the control system activates a system-ready indicator.

Abstract: A small watercraft includes a hull, an internal combustion engine and an engine speed limiting arrangement. The hull defines an engine compartment in which the engine is supported. The engine speed limiting arrangement comprises an engine condition sensor and an electronic control unit that is operatively connected to the engine condition sensor. The engine speed limiting arrangement is configured to regulate the engine speed of the engine such that the engine speed remains between a maximum value above which the engine can be damaged and a minimum value below which the watercraft will no longer stay in a planing state. Methods for operating the engine speed limiting arrangement are also disclosed.

Abstract: An exhaust pipe cooling system regulates the temperature of a exhaust system catalyzer on a small watercraft to ensure proper functioning and to inhibit overheating of the catalyzer. The cooling system supplies fresh water to a water jacket which surrounds the catalyzer in a manner independent of an engine cooling system. The cooling system also supplies fresh water to an upwardly oriented discharge nozzle. The upward water jet from the nozzle spays well above the surface of the body of water in which the watercraft is operated to provide a visible indicator of location of the small watercraft. A control valve 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: 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 watercraft includes a monitoring and control system to sense the operational state of a catalytic device and a cooling system used with an exhaust system of the watercraft. The monitoring and control system receives temperature reading from an exhaust system temperature sensor. The sensor desirably is located in a portion of the exhaust system which the cooling system cools. The monitor and control system activates a first level warning indicators if the sensed temperature of the exhaust system exceeds a preselected first warning temperature. And if the sensed temperature exceeds a presented second warning temperature, the monitoring and control system reduces engine speed and eventually stops the engine. The monitor and control system also communicate with an exhaust gas temperature sensor which is located in the vicinity of a catalytic device of the exhaust system. If the sensed temperature is within a desired temperature range, the control system activates a system-ready indicator.

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 a hull, an internal combustion engine and an engine speed limiting arrangement. The hull defines an engine compartment in which the engine is supported. The engine speed limiting arrangement comprises an engine condition sensor and an electronic control unit that is operatively connected to the engine condition sensor. The engine speed limiting arrangement is configured to regulate the engine speed of the engine such that the engine speed remains between a maximum value above which the engine can be damaged and a minimum value below which the watercraft will no longer stay in a planing state. Methods for operating the engine speed limiting arrangement are also disclosed.

Abstract: An improved fuel delivery and injection system for a small watercraft engine reduces the heat effects within an enclosed engine compartment upon a fuel pump of and the fuel within a fuel injection system. The fuel delivery system includes a vapor separator and a high-pressure fuel pump. The fuel pump is at least partially located within the vapor separator. The fuel within the vapor separator cools the fuel pump. The vapor separator also is positioned between a pair of air ducts such that an air stream between the ducts cools the fuel within the vapor separator. This arrangement consequently improves the consistency of the air/fuel ratio in the fuel charges delivered to the engine cylinders, provides a compact structure between the fuel pump, and the vapor separator and improves the durability of the fuel pump.

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 watercraft includes an improved engine control system that enhances the responsiveness of the watercraft and eases watercraft operation. The watercraft includes a propulsion device, such as a jet propulsion unit, and an engine that powers the propulsion device. The engine control system is configured to maintain or increase engine speed under certain operating conditions.

Abstract: An improved fuel delivery and injection system for a small watercraft engine reduces the heat effects within an enclosed engine compartment upon a fuel pump of and the fuel within a fuel injection system. The fuel delivery system includes a vapor separator and a high-pressure fuel pump. The fuel pump is at least partially located within the vapor separator. The fuel within the vapor separator cools the fuel pump. The vapor separator also is positioned between a pair of air ducts such that an air stream between the ducts cools the fuel within the vapor separator. This arrangement consequently improves the consistency of the air/fuel ratio in the fuel charges delivered to the engine cylinders, provides a compact structure between the fuel pump, and the vapor separator and improves the durability of the fuel pump.

Abstract: A watercraft includes a monitoring and control system to sense the operational state of a catalytic device and a cooling system used with an exhaust system of the watercraft. The monitoring and control system receives temperature reading from an exhaust system temperature sensor. The sensor desirably is located in a portion of the exhaust system which the cooling system cools. The monitor and control system activates a first level warning indicators if the sensed temperature of the exhaust system exceeds a preselected first warning temperature. And if the sensed temperature exceeds a presented second warning temperature, the monitoring and control system reduces engine speed and eventually stops the engine. The monitor and control system also communicate with an exhaust gas temperature sensor which is located in the vicinity of a catalytic device of the exhaust system. If the sensed temperature is within a desired temperature range, the control system activates a system-ready indicator.

Abstract: An improved arrangement of a fuel injection system within a personal watercraft reduces the likelihood that certain sensitive components of the fuel injection system will contact water, regardless of the orientation in which the watercraft floats. Because of the sporty nature of personal watercraft, these boats often are inverted or laid on their sides. The fuel injectors of the fuel injection system are positioned within an engine compartment of the watercraft so as to remain above the water surface level with the watercraft in any orientation. In one mode, the fuel injectors also are positioned above the ends of air ducts through which air is introduced into the engine compartment. The fuel injectors are also shielded by protective covers. As a result, the occurrences of water contacting the fuel injectors is reduced.

Abstract: A small watercraft includes an improved fuel supply system that is configured and arranged to provide a compact engine design while promoting air cooling of at least a portion of the fuel supply system. In one mode, a fuel pump of the system is at least partially located within an air flow path between an outlet of an air duct and an inlet of the engine induction system. The air flow cools the fuel pump to reduce its operating temperature. As a result, the durability and performance of the fuel pump is improved despite the fuel pump lying in close proximity to the engine's exhaust system. Shock-absorbent mounts also couple at least a portion of the fuel supply system (e.g., the fuel pump and a fuel delivery rail) to the hull of the watercraft. These fuel system components consequently experience lessened impact when the watercraft skips over the body of water on which it is planing, and are thus less susceptible to breakage.

Abstract: A number of embodiments of personal watercraft having engines that employ fuel air injection systems. The fuel air injection system is protected from water ingestion by placing its inlet in an area that will be above the water level regardless of whether the watercraft is operating upright or is inverted and during the transition between those positions. In addition, an arrangement is provided for cooling the air compressor so as to improve efficiency.

Abstract: A number of embodiments of personal watercraft incorporating direct cylinder injected two cycle crankcase compression engines. In all embodiments, the fuel injector is positioned so that it will be protected by either or both of the exhaust and intake systems of the engine from damage and also from water vapor while still affording ease of accessibility therefore. A variety of injector and associated spark plug locations are depicted.

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.