Abstract: A number of embodiments of four cycle outboard motors that have water cooled engines and an oil pan that is formed in the upper portion of the drive shaft housing. An exhaust pipe collects exhaust gases from an exhaust guide and delivers to a cavity that is formed in the oil pan by an interior wall thereof In many embodiments the exhaust pipe does not terminate below the lower surface of the oil pan and several arrangements are disclosed for delivering idle exhaust gases to the area between the exterior of the exhaust pipe and the interior surface of the oil pan that defines the cavity. Various arrangements are disclosed for conveying idle exhaust gases to this area and discharging them to the atmosphere through and above the water exhaust gas discharge. These arrangements incorporate a system for precluding water from entering into the engine through its exhaust system including the idle discharge.

Abstract: An outboard drive is equipped with a water inlet located on a lower casing of the outboard drive. The lower casing includes a nacelle that houses a transmission and a propulsion shaft that are coupled to an engine through a drive train. The propulsion shaft rotates about a longitudinal axis that is aligned with a centerline of the nacelle. The water inlet is located on a front, cone-shaped nose of the nacelle, forward of the transmission and above the longitudinal axis of the of the propulsion shaft. The water inlet communicates with a water passage that guides cooling water to a water pump. The water passage is located in front of the transmission in order to increase the size of the water passage over prior water cooling systems of outboard drives.

Abstract: An intake manifold for an engine powering a water propulsion device of an outboard motor is disclosed. The engine has first and second combustion chambers and an intake system for delivering a fuel and air charge to each combustion chamber. The intake system includes a first intake passage leading through the engine to the first combustion chamber and a second intake passage leading through the engine to the second combustion chamber, the first intake passage positioned vertically above the second intake passage. The intake manifold is arranged to deliver equal amounts of fuel to the first and second intake passages and includes a main passage extending along a first axis. A first branch defines a passage leading the main passage to the first intake passage, and a second branch defines a passage leading from said main passage to the second intake passage.

Abstract: A throttle control system for an outboard motor and throttle position sensor therefor that permits a compact assembly by operating the throttle valve via an intermediate throttle valve operating shaft that is disposed closer to the body of the engine and farther from the protective cowling than the throttle valve. A throttle position sensor is associated with this intermediate throttle operating shaft for providing a signal indicative of throttle valve position for engine control.

Abstract: A cowling arrangement for an outboard motor for use in powering a watercraft is disclosed. The motor has an engine and a water propulsion device, the engine having an output shaft arranged to drive the water propulsion device. The engine has a body with a top end and a bottom end, the output shaft extending above the top end. A flywheel is connected to the output shaft at the top end of the engine, and a flywheel cover is positioned over the flywheel and supported by the engine body. The cowling defines an engine compartment in which the engine is positioned and has an opening therein. A starter panel is connected to the flywheel and supported solely thereby, the starter panel cooperating with the cowling to close the opening therein, the starter panel supporting at least one component of a starter for the engine.

Abstract: The present invention is an overheat detection system for an engine having at least one cooling jacket which is drained of coolant when the engine stops running. The detection system includes a sensor for sensing a temperature associated with the cooling jacket. The detection system is arranged to output an overheat signal in the event the temperature sensed by the sensor is above a predetermined temperature except within a predetermined time after the engine has been started.

Abstract: The invention relates to an engine control system for an internal combustion engine for propulsion of an associated watercraft. The engine includes an air intake in communication with a combustion chamber of the engine and an air intake adjustment means for altering the amount of air let into the combustion chamber of the engine. There is also an operation device controlling a water propulsion device of the watercraft. The device is movable between a forward, a neutral or a reverse position. A first control means for controls the air intake adjustment means based upon the position of the movable operating device. A second control means controls the air intake adjustment means independent of the first control means based upon a set of predetermined conditions.

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 fuel system for an internal combustion engine powering an outboard motor of a watercraft is disclosed. The fuel system includes a main fuel source and a pump for delivering fuel from the main fuel source through a fuel filter to a vapor separator. Fuel is supplied from the chamber by high pressure pump through a fuel rail to one or more fuel injectors. Undelivered fuel is returned to the vapor separator through a return line. Oil is mixed into the fuel between the fuel filter and the high pressure pump, so that the high pressure pump draws a mixture of fuel and oil and delivers it to the charge former(s) and fuel return.

Abstract: A vapor separator for an outboard motor is disclosed. The outboard motor has a cowling and a water propulsion device. An internal combustion engine is positioned in the cowling and arranged to propel the water propulsion device. The engine includes a top and a bottom side. The engine also includes an engine block defining at least one cylinder bore therein. A crankshaft is supported for rotation with respect to the engine block and is located in a first chamber. A camshaft is supported for rotation with respect to the engine block and is located in a second chamber. The engine further includes a lubrication system for the lubrication of the crankshaft and the camshaft. A lubrication collection area is located on the bottom side of the engine for the gravitational collection of engine lubrication fluid from the first chamber and the second chamber.

Abstract: A choke control for an outboard motor having a cowling, a water propulsion device and an internal combustion engine positioned in the cowling and arranged to propel the water propulsion device is disclosed. The engine has at least one combustion chamber and an intake system including an intake pipe extending along a side of the engine for providing air to the combustion chamber. A choke control is provided for actuating a choke valve associated with the intake pipe. The choke control includes a choke actuator which is positioned exterior to the cowling and supported by a mount associated with the cowling, the choke actuator connected to the choke valve via a choke linkage which is positioned within the cowling generally above the intake pipe.

Abstract: An induction system for an internal combustion engine powering an outboard motor, the motor having a cowling and a water propulsion device and the engine positioned in the cowling and having an output shaft arranged to drive the water propulsion device, is disclosed. The engine has at least one combustion chamber, and the induction system is arranged to provide air to each combustion chamber. The induction system includes an intake duct having an inlet and an outlet and defining an air flow path extending from the inlet to the outlet, the inlet defining an opening through which air is drawn, the outlet arranged to deliver air passing through the duct to an intake passage leading to the combustion chamber. At least one electrical component associated with said motor is connected to the intake duct and extends into the air flow path defined therethrough, whereby the at least one component is cooled by the flow of air through the duct.

Abstract: A fuel supply system includes a fuel pump for providing fuel from a fuel source to an electrically operated fuel injector for injection into a combustion chamber of an engine. The fuel pump has a follower driven pumping element. The follower is actuated by a cam element, with movement of the cam element powering the follower, effecting pumping by the pump. The cam element is rotated by a crankshaft of the engine.

Abstract: A pull starter for an engine powering an outboard motor having a cowling and a water propulsion device is disclosed. The engine is positioned in the cowling and has a generally vertically extending crankshaft. A lower end of the crankshaft is arranged to drive the water propulsion device. The starter includes a drum connected to the crankshaft at a top end of the engine, a starter cord having a first end connected to the drum and a second end connected to a handle, and a cord guide for guiding the cord through the cowling, the cord guide including an arcuate cord-engaging surface. The cord extends through said cowling in a first direction and is then guided by the arcuate surface of the cord guide into a second direction to the drum.

Abstract: A tilt and trim control system includes a simply-structured control unit that better protects its electrical components from contact with water and other contaminates. The control unit includes a pair of relays mounted onto to a printed circuit board. The board and the relays are potted within a housing. A plurality of wire leads are also attached to the printed circuit board with the connections between the leads and the board also being potted. The control unit is attached to the lower section of a cowling that surrounds an engine of the marine drive. The tilt and trim control system additionally includes a terminal block that is positioned within the cowling. The terminal block connects the control unit to a motor of a tilt and trim mechanism, and is positioned above the control unit on the engine. This position of the terminal block generally isolates the terminal block from water that may lie within the lower section of the cowling.

Abstract: The present invention is an electrical system for an engine of the type used to power a watercraft. A primary power supply of the system is connected to a main circuit by a feed circuit. A main switch controls the flow of power from the primary power supply to the main circuit through the feed circuit. An auxiliary power supply is connected to the main circuit in a manner which allows power to flow from the auxiliary power supply to the main circuit even if the main switch is preventing power to flow from the primary power supply to the main circuit.

Abstract: The present invention is an engine control for an internal combustion engine having at least one combustion chamber and an air/fuel charging system for delivering an air and fuel charge to the combustion chamber for combustion therein. The control includes an oxygen sensor associated with the combustion chamber, the sensor providing feedback data based upon the air/fuel ratio of the charge supplied to the combustion chamber. The control also includes at least one sensor for sensing a condition other than the air/fuel ratio in the combustion chamber which affects the output of the oxygen sensor. The control adjusts the air/fuel ratio of the charge delivered to the combustion chamber towards a target value based upon the output of the oxygen sensor, the control arranged to adjust the target value based upon the output of the at least one sensor sensing an operating condition other than the air/fuel ratio.

Abstract: An arrangement for an engine positioned in a cowling of an outboard motor and having an output shaft arranged to drive a water propulsion device of the motor is disclosed. The engine has a first end and a second end and a centerline passing through the ends, at least one combustion chamber, an intake system positioned along a first side of the engine for delivering air to the combustion chamber, a lubricating system including an oil filter for delivering lubricant to the engine and an ignition system including an ignition coil for charging an ignition element corresponding to the combustion chamber. The ignition coil and oil filter are positioned along a second side of the engine opposite the intake system and arranged to reduce the transfer of heat from the filter to the coil, with the oil filter having an outermost portion which is positioned outwardly of the engine between the centerline and a second line which extends parallel to the centerline and passes through an outermost portion of the ignition coil.

Abstract: A hydraulic arrangement for controlling the tilt and trim of an outboard drive. The hydraulic arrangement comprises a single cylinder assembly having a single bore inside wherein two separate pistons are supported for reciprocation and sealed to the cylinder with piston seals. The lower piston is connected to a valve mechanism that selectively opens or closes a cylinder relief hole depending upon the position of the piston within the cylinder. The valve mechanism operates so that the piston seals never contact the relief hole to prevent premature failure of the piston seals.