Abstract: An induction system arrangement for an engine powering an outboard motor is disclosed. The engine has a block defining at least one combustion chamber which a member movably mounted therein which is connected to a crankshaft for driving the crankshaft. A throttle body is connected to the block and has a throttle passage leading from an inlet to the block. An air plenum is positioned at the inlet of the throttle body. A fuel injector is mounted to exterior of the throttle body corresponding to each throttle passage. The air plenum has an air inlet through which air is supplied to the engine, the air inlet positioned on a side of the throttle body opposite the fuel injectors.

Abstract: A fuel injection system for an internal combustion engine of the type utilized to power an outboard motor of a watercraft is disclosed. The engine is oriented with its crankshaft vertically extending, such that the engine has a top and a bottom, a first end and a second end, and a side between the ends. An air delivery passage extends generally from the first end along said side to an intake passage leading through the engine to a combustion chamber therein. A fuel injector is positioned along the side of the engine and arranged to deliver fuel into air flowing through the passage. In one arrangement, the fuel injector is connected to an intake manifold defining at least a part of the air delivery passage and is adapted to deliver fuel opposite the flow of air through the passage at the point of delivery. In a second embodiment, the fuel injector is positioned between the air delivery passage and the side of the engine.

Abstract: An exhaust system for an outboard motor powered by an internal combustion engine is disclosed. Preferably, the engine is of the "V"-type, having first and second banks defined by first and second cylinder heads connected to a cylinder block. Each bank contains at least one combustion chamber, and the banks define a valley extending therebetween along a length of the engine. A main exhaust passage is defined through each cylinder head generally within the valley, and an exhaust passage extends from each combustion chamber of a bank to the main exhaust passage of that bank. The main exhaust passages of the two banks join into a single passage.

Abstract: A fuel supply system for providing fuel from a fuel source to a combustion chamber of an engine is disclosed. The fuel supply system includes a vapor separator in which vapor is separated from fuel supplied from the fuel source. A pre-pressurizing pump pressurizes fuel from the vapor separator to a first pressure and delivers it to a high pressure pump. The high pressure pump pressurizes the fuel to a pressure above the first pressure and delivers it to a fuel injector for delivery into the combustion chamber. Preferably, a fuel cooler is provided between the vapor separator and high pressure pump for cooling the fuel. In addition, a valve is diverts a portion of the fuel supplied by the high pressure pump back to the vapor separator.

Abstract: A propulsion system includes an improved propeller design which increases the durability of the propeller for enhanced rotational vibration damping, while simplifying the structure of the propeller. A rubber coupling is placed within a space that is secured between a propeller hub and an inner member of the propeller. The rubber coupling resiliently couples the propeller hub to the inner member with only the inner member and the propeller hub maintaining the space in which the rubber coupling is placed. The substantially constant size of the space generally isolates the rubber coupling from cyclic tension and compression stresses in the axiel and radial directions as the propeller rotates to improve the durability of the rubber coupling.

Abstract: An engine having an engine control for reducing the passage of unburned fuel and other components into the exhaust system for preventing the fouling of an exhaust catalyst, is provided. As the speed of the engine increases, the engine control causes a valve corresponding to each exhaust passage to move to a position whereby time during which exhaust is allowed to flow from each combustion chamber is extended. Preferably the valve is of the rotating type, movable from one position in which it does not obscure the exhaust passage and the exhaust duration is long, and a second position in which it does obscure a portion of the exhaust passage, causing the exhaust start time to be delayed and the exhaust stop time to be accelerated. The engine control prevents fouling of the catalyst by reducing the flow of unburned fuel products through the exhaust thereto.

Abstract: A fuel injection system for an internal combustion engine provides a uniform flow of gaseous and liquid fuel to each of the intake passages of the engine. A balance passage interconnects each of the intake manifolds to each other and balances the pressure within the intake passages. A pressure regulator regulates the fuel pressure at the fuel injector. A reference pressure chamber within the pressure regulator communicates with the balance passage and controls the fuel pressure based on the balanced pressure within intake passages. The balance passage also communicates with a vapor separator of the fuel supply system that separates liquid fuel from gaseous fuel. The balance passage promotes even distribution of the gaseous fuel to the intake passages. The fuel injection system also includes plenum chamber that acts a source of air for the engine. The plenum chamber includes an drain outlet that communicates with the balance passage for returning blown back fuel from the plenum chamber to the intake passages.

Abstract: Several embodiments of bilge devices for small watercraft that permit the use of small capacity bilge pumps and which ensure that the bilge pumps will not run dry during abrupt maneuvers are disclosed. This result is obtained by using a trap-like device that permits water to accumulate from the bilge but which restricts the escape of the water during abrupt maneuvers.

Abstract: A fuel injection system for an internal combustion engine of the type utilized to power an outboard motor of a watercraft is disclosed. The engine is oriented with its crankshaft vertically extending, such that the engine has a top and a bottom, a first end and a second end, and a side between the ends. An air delivery passage extends generally from the first end along said side to an intake passage leading through the engine to a combustion chamber therein. A fuel injector is positioned along the side of the engine and arranged to deliver fuel into air flowing through the passage. In one arrangement, the fuel injector is connected to an intake manifold defining at least a part of the air delivery passage and is adapted to deliver fuel opposite the flow of air through the passage at the point of delivery. In a second embodiment, the fuel injector is positioned between the air delivery passage and the side of the engine.

Abstract: A liquid cooling system for an internal combustion engine of an outboard motor is disclosed. The cooling system includes a pump for delivering coolant to one or more coolant passages in the engine. At least one thermostat is provided for controlling the flow of coolant through the engine to one or more return lines which extend to a coolant pool extending about a lubricating oil reservoir. A pressure relief valve is provided between the pump and thermostat for relieving coolant from the engine upon excessive coolant pressure. The relieved coolant is preferably either delivered to a drain, a second coolant pool extending about a muffler, or the first coolant pool. Preferably, a diverter is provided for controlling the flow of the relieved coolant.

Abstract: An engine includes an improved throttle control to enhance engine performance. The throttle valves within the engine are arranged to rotate about an axis with is generally parallel to a direction in which a distance between intake branch passages increases as the intake branch passages diverge apart. The uniformity of the amount of air delivered to each branch passage is thus improved to produce more complete and consistent combustion within the respective combustion chamber. In addition, the pitch between the throttle valves as arranged on the engine generally matches the pitch between the cylinders of the engine in order to standardize the length and shape of the induction paths from the throttle valves to the respective cylinder. Improved consistency between the cylinders of the amount of air charge delivered to each cylinder results from this arrangement.

Abstract: An oil pump for an engine of an outboard motor of the type including a block with an output shaft extending therefrom is disclosed. The oil pump includes an oil pan comprising an outer housing defining an oil chamber and a pumping chamber therein. The oil pump includes a pumping mechanism for pumping oil from the oil chamber to the engine. The pumping mechanism is positioned within the pumping chamber, with the outer housing defining the pumping chamber acting as a pump housing therefor. The pumping mechanism is positioned on and driven by the output shaft of the engine which extends through the oil and pumping chambers of the oil pan. A recess in the pumping chamber accomodates a flywheel, which is also positioned on and driven by the output shaft of the engine.

Abstract: A cowling for an outboard motor of the type having a water propulsion device powered by an internal combustion engine positioned within an engine compartment defined by the cowling, is disclosed. The cowling has at least one intake vent positioned therein and includes an engine cover which defines an isolated intake air path from the vent across a top end of the engine to an engine air intake. The cover also defines a chamber in which a flywheel rotated by the crankshaft at the top end of the engine is positioned. The chamber has an inlet in communication with the engine compartment, and an outlet leading to an exhaust passage. The exhaust passage leads to an exhaust vent in the cowling.

Abstract: A coolant system for a vertically oriented engine of an outboard motor is disclosed. Coolant flows through the coolant system from a coolant pump into a coolant jacket surrounding an exhaust manifold of the engine, down to a bottom of a cylinder head of the engine, through the cylinder head an engine block, through a thermostat, and then to a jacket positioned along an exhaust pipe leading from the exhaust manifold, to a coolant discharge.

Abstract: A fuel supply system for an engine powering an outboard motor is disclosed. The fuel supply system includes a first pump for delivering fuel from a fuel supply to a fuel reservoir located at the motor. Another pump delivers fuel from the reservoir to a charge former. The rate of fuel delivery into the reservoir is regulated by a valve based upon the level of the fuel within the reservoir. A flow rate sensor is provided for sensing the fuel flow rate into the reservoir. The fuel system is arranged to limit a change in sensed fuel flow rate when a position of the motor is changed, such as when the motor is trimmed.

Abstract: A drive arrangement for an engine positioned within a cowling of an outboard motor and powering a water propulsion device of the motor is disclosed. Preferably, the engine is of the "V"-type, having first and second banks and an intake and exhaust camshaft corresponding to each bank. A drive arrangement is provided for driving the camshafts off of a crankshaft of the engine. Preferably, a flexible transmitter is positioned at a bottom end of the engine and directly drives one camshaft of each bank from the crankshaft, with the other camshaft of each bank driven by the driven camshaft.

Abstract: An outboard motor includes a fuel supply system which minimizes and curbs fuel spillage when the outboard motor is placed in a non-upright position. The fuel supply system includes an internal fuel tank which communicates with at least one intake passage of an engine of the outboard motor via a fuel vapor discharge line. The discharge line extends between a vapor discharge port on the fuel tank and a vapor suction port on the engine. The ports and the discharge line are arranged within the outboard motor to inhibit significant spillage or drainage of liquid fuel from the fuel tank through the vapor discharge line regardless of the orientation of the outboard motor, such as, for example, when the outboard motor is inverted or is laid over on its side.

Abstract: An exhaust system for an outboard motor discharges exhaust gases in front of the propeller for improved acceleration. The discharge of exhaust gases upstream of the propeller produces a cavitation effect about propeller blades when accelerating from low speeds. As a result, the outboard motor accelerates more rapidly. At high speeds, the exhaust gases flow through the propeller hub and discharge behind the propeller. No substantial cavitation effect occurs about the blades, and thus, no significant loss of propulsion efficiency occurs when traveling at high speeds. When quickly reversing the propeller to produce a rapid braking force, the exhaust gases are directed away from the propeller blades to inhibit cavitation about the propeller blades and improve braking efficiency.

Abstract: A compact vapor separator for a fuel injection system reduces the size of the fuel system mounted on the side of an outboard engine. The girth of the outboard motor's power head consequently is decreased. In one embodiment, the vapor separator employs a plurality of rotary vane-type pumps. The pumps are sized to produce a sufficient flow rate and fuel pressure, while minimizing power consumption. At least one of the fuel pumps can be located on a periphery of a housing of the vapor separator and can be removably attached thereto to facilitate easy removal and assembly for service and repair. The vapor separator also can include a redundant seal arrangement to generally isolate an exterior casing of the fuel pump from the fuel and to seal an upper end of the housing. In another embodiment, a dividing wall separates the fuel pump from an fuel supply inlet of the fuel tank. The wall inhibits gas bubble migration toward the inlet of the fuel pump. The fuel pump thus draws less vapor.

Abstract: A number of embodiments of induction systems for outboard motors wherein the induction system can be tuned to provide good performance under high low speed by utilizing two plenum chambers and a control for controlling the effective length of the intake passage serving the combustion chamber. Both inline and V-type embodiments are disclosed.