Abstract: A small watercraft with an emergency shut-off system is provided. The emergency shut-off system is configured to shut off the engine of the small watercraft when the small watercraft is overturned. The emergency shut-off system comprises an electronic control unit that is operatively coupled to an overturn sensor and the engine. The electronic control unit is configured to sense a signal generated by the overturn switch. The electronic control unit is also configured to determine if the signal generated by the overturn switch continues for a period longer than a preset amount of time and to shut off the engine if the signal generated by the overturn switch continues beyond the preset amount of time.

Abstract: A watercraft includes a lubrication system having a lubrication reservoir and a lubricant pump assembly. The lubricant reservoir can be constructed from an upper portion connected to a separate lower portion. The pump assembly can be co-axially aligned with and driven by the crankshaft of the engine.

Abstract: A watercraft includes an internal combustion engine mounted such that its crankshaft extends vertically. A gearbox is arranged beneath the engine and includes engine mounts attached directly thereto for mounting the engine to a mounting surface within the engine compartment. Thus, the engine may be mounted compactly arranged in the rear of the watercraft, thus minimizing the overall length of the engine compartment. Additionally, the engine mounts allow the engine to be mounted conveniently within a watercraft in a vertical orientation. The gear box may also include at least a portion of an exhaust conduit extending therethrough. The gear box may be also utilized as a lubricant reservoir for a lubrication system of the engine. Additionally, the exhaust conduit passing through the gear box may include a cooling jacket, thus protecting oil in the gear box from the heat emitted from the exhaust conduit therein.

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: Various embodiments of an exhaust system for an engine powering a water propulsion device of a watercraft having a hull with a front end and a rear end are disclosed. The water propulsion device is positioned near the rear end of the watercraft, with the engine connected to the hull and positioned generally towards the front end of the watercraft from the water propulsion device and having an output shaft arranged to drive the water propulsion device. The exhaust system routes exhaust from each cylinder or combustion chamber of the engine to a discharge at the rear end of the watercraft.

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 planing watercraft including a hull, a propulsion unit mounted on the hull and a high RPM—high output engine for driving the propulsion unit, wherein the engine includes at least one intake valve and an intake valve timing control system for advancing the opening and closing of the intake valve when the watercraft is operating below a predetermined speed corresponding to a velocity at which the watercraft transitions from non-planing to planing motion. The engine may also include a long air intake passage for low-speed operation and a short air intake passage for high-speed operation, with an air intake control valve in the short air intake passage that is closed when the watercraft is operating below the predetermined speed. The engine may also include an exhaust control valve for constricting the exhaust passage, and a system for at least partially closing the exhaust control valve when the watercraft is operating below the predetermined speed.

Abstract: A diagnostic system is provided to aid a technician or engineer in diagnosing an internal combustion engine. The diagnostic system comprises an electronic control unit that is operatively coupled to a data storage device and to one or more engine sensors. The electronic control unit is configured to collect data from the one or more engine sensors and to store that data in the data storage device. A computer is selectively coupled to the data storage device. The computer program is configured to display specific sets of data stored in the data storage device in various formats.

Abstract: Several embodiments of personal watercraft having a V bottom hulls that define an engine compartment in which an internal combustion engine is positioned. This engine drives a propulsion device for the watercraft through an appropriate transmission. The engine includes an engine body having an opening into which a fuel injector injects. The fuel injector is positioned so that its spray axis is oriented so that it is not likely to intersect the walls of the engine that define the opening regardless of the angular position of the watercraft in the body of water in which it is operating. Both direct and manifold injected and two and four cycle engines are disclosed.

Abstract: A small planing watercraft including a hull, a propulsion unit mounted on the hull and a high RPM—high output engine for driving the propulsion unit, wherein the engine includes at least one intake valve and an intake valve timing control system for advancing the opening and closing of the intake valve when the watercraft is operating below a predetermined speed corresponding to a velocity at which the watercraft transitions from non-planing to planing motion. The engine may also include a long air intake passage for low-speed operation and a short air intake passage for high-speed operation, with an air intake control valve in the short air intake passage that is closed when the watercraft is operating below the predetermined speed. The engine may also include an exhaust control valve for constricting the exhaust passage, and a system for at least partially closing the exhaust control valve when the watercraft is operating below the predetermined speed.

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: Several embodiments of personal watercraft employing exhaust systems that incorporate not only a catalyst, but also an exhaust silencing device for silencing the sounds of the exhaust gases. The components are laid out in such a way that there will be minimum heat transfer from the exhaust gases to the engine compartment, and also so that there will be a cooling air flow across the exhaust system to further provide this result. In one embodiment, the silencing device is mounted transversely at the front of the engine, and in other embodiments it is disposed longitudinally to the rear of the engine. In all embodiments, the components are laid out to maintain good fore and aft and side to side balance.

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 four cycle power personal watercraft having an improved crankcase ventilating and induction system. The crankcase ventilating system ensures that the crankcase gases will be passed to the combustion chambers to eliminate unburned hydrocarbons from escaping to the atmosphere. However, the system is also designed so as to preclude separated lubricant from passing into the induction system and also to prevent water from entering the engine through the induction system or the ventilating system.

Abstract: Various embodiments of an exhaust system for an engine powering a water propulsion device of a watercraft having a hull with a front end and a rear end are disclosed. The water propulsion device is positioned near the rear end of the watercraft, with the engine connected to the hull and positioned generally towards the front end of the watercraft from the water propulsion device and having an output shaft arranged to drive the water propulsion device. The exhaust system routes exhaust from each cylinder or combustion chamber of the engine to a discharge at the rear end of the watercraft.

Abstract: A small planing personal watercraft including a hull, a straddle-type seat atop the deck of the hull, and a four cycle engine located internally of the hull is provided with one or more engine air intake tubes extending approximately horizontally in the hull in its normal flotation position. A carburetor supplying fuel to the engine intake air is located in the intake tube with a pivoting throttle valve located in the carburetor. The pivot axis of the throttle valve is oriented vertically relative to the carburetor and intake tube. An access opening is provided above the engine and various fuel control elements are disposed so they are readily accessible through the access opening.

Abstract: An engine arrangement for a personal watercraft having electrically operated fuel injectors. The cam cover of the cylinder head has a portion that extends in overlying relationship to the fuel injectors so as to protect the terminal ends thereof from water intrusion without inhibiting the accessibility of the fuel injectors for its servicing.

Abstract: A small watercraft includes a four-cycle engine which is arranged within a hull of the watercraft to enhance ventilation of and air induction into the engine. The hull includes at least one air duct which opens into an engine compartment within the hull at a level below an upper rim of the flywheel. A case cover of the flywheel assembly acts as a guide to direct at least a portion of the air flow, which enters the engine compartment at this location, upward over the engine and toward the engine's air intake. The engine also can be oriented to angle its output shaft relative to a keel line of the hull in order to provide ample space for a sufficiently sized flywheel assembly, as well as to decrease the distance between the bottom of the watercraft and the axis of the impeller shaft. As a result, the length from the gullet inlet and to the impeller is shortened to improve pumping efficiency and thus enhance thrust performance.

Abstract: A jet propulsion system for a watercraft wherein the jet propulsion outer housing has the impeller shaft portion in which the impeller is journaled for rotation about an impeller shaft axis disposed at an angle to the discharge nozzle rather than concentric with it as previously utilized. This permits the appropriate trim angle for the discharge nozzle while, at the same time, permitting the engine to be mounted relatively high in the hull so as to afford adequate clearance on the underside of the engine for such things as increasing the oil capacity for four cycle wet sump engines are employed.

Abstract: A two-cycle internal combustion engine for a watercraft that includes a cylinder block having a cylinder bore, a piston reciprocating in the cylinder bore and an exhaust port formed in the cylinder block. An exhaust path extends from the cylinder bore for exhausting combustion products from the cylinder bore. An exhaust control valve cooperates with the exhaust port and is movable between at least a first position for advancing the closing of the exhaust port so as to increase the compression ratio in the engine and a second position for delaying the closing of the exhaust port so as to decrease the compression ratio in the engine. Means for controlling the exhaust control valve between the first and second position are provided and are controlled in response to a watercraft condition.