Abstract: An outboard has a housing unit mounted on an associated watercraft. An engine is disposed on the housing unit. A cowling surrounds the engine. The cowling has an inlet port through which atmospheric air enters inside of the cowling. At least a substantial portion of the cowling is made of a nonferrous metal.

Abstract: An engine includes an engine body that defines first and second banks arranged in a V-shape. A crankshaft extends within the engine body. First and second camshafts extend within the first bank, and third and fourth camshafts extend within the second bank. The first, second, third and fourth camshafts are generally disposed parallel to each other and parallel to the crankshaft. The first and third camshafts are placed next to each other. A first flexible transmitter surrounds the crankshaft and the first and third camshafts. The crankshaft drives the first and third camshafts through the first transmitter. A second flexible transmitter surrounds the second and fourth camshafts and either the first or third camshaft. The first or third camshaft drives the second and fourth camshafts through the second transmitter. The engine also includes VVT mechanisms to change an angular position of the camshafts relative to the crankshaft. The VVT mechanisms are disposed at the camshafts.

Abstract: A marine drive has an engine, a propeller and a transmission to switch the propeller between a propulsion position and a non-propulsion position. The engine has a combustion chamber. An air induction system communicates with the combustion chamber through an intake port. An exhaust system communicates with the combustion chamber through an exhaust port. Intake and exhaust valves move between an open position and a closed position of the intake port and the exhaust port, respectively. Intake and exhaust camshafts actuate the intake and exhaust valves, respectively. A VVT mechanism changes an actuating timing of the intake camshaft at which the camshaft actuates the intake valve. An ECU controls the intake camshaft to set the actuating timing at a generally optimum timing. A transmission position change operation sensor senses that the transmission is under operation and sends a signal to the ECU. The ECU controls the VVT mechanism based upon the signal to move the actuating timing away from the optimum timing.

Abstract: An engine has a combustion chamber. An air induction system communicates with the combustion chamber through an intake port. An exhaust system communicates with the combustion chamber through an exhaust port. Intake and exhaust valves move between an opening position and a closing position of the intake port and the exhaust port, respectively. A camshaft actuates either the intake valve or the exhaust valve. The camshaft extends generally vertically. A VVT mechanism changes an angular position of the camshaft. A sensor detects the angular position and generates a signal indicative of the angular position. The sensor is disposed below the VVT mechanism.

Abstract: An exhaust system for an internal combustion engine of an outboard motor is provided. The exhaust system provides dual exhaust passages, simplifying the engine's construction and reducing manufacturing costs, while optimizing engine performance. The exhaust system includes exhaust ports having equal lengths that avoid differential pressure losses across cylinders. The arrangement of the exhaust passages enables a cowling to have a tapered aerodynamic design.

Abstract: An air intake system for an engine of an outboard motor includes air intake plenum chambers and corresponding air intake passages. Residual condensed fuel that can accumulate in the plenum chamber is guided to lower air intake passages through a slot at a predetermined rate to be delivered to combustion chambers inside the engine. The air intake system can reduce the likelihood that the plenum chambers will accumulate residual fuel above an acceptable amount and can allow the residual fuel to be more slowly delivered to the engine so as to evacuate the fuel without substantially altering the desired air/fuel ratio.

Abstract: An integrated direct fuel injector position is incorporated providing better fuel atomization within the combustion chamber. The direct fuel injector position is integrated between within an intake passage body and a cylinder head assembly eliminating the need for additional fuel delivery conduits, thus decreasing the size of the engine and lowering the production costs of the outboard motor. The direct fuel injector position permits immediate air/fuel mixture adjustments allowing for improved acceleration enrichment and lean stratified charge operation. The integrated direct fuel injector position enables the operator to enjoy compact engine design, improved engine performance and increased fuel efficiency.

Abstract: A watercraft engine fuel cooling system that cools a fuel vapor separator through a detachable heat exchanger. The detachable heat exchanger allows for inexpensive replacement of the detachable heat exchanger if the heat exchanger should become damaged from corrosion. The detachable heat exchanger can transfer the heat from the vapor separator through a water cooling jacket, a thermoelectric element, or through fins to the surrounding air. The transfer of heat from the fuel vapor separator allows the fuel to be kept within a predetermined fuel temperature range.

Abstract: An engine for a marine drive has a combustion chamber. An engine body of the engine defines intake and exhaust ports communicating with the combustion chamber. An air induction system communicates with the combustion chamber through intake ports. An exhaust system communicates with the combustion chamber through the exhaust ports. Intake valves move between an opening position and a closing position of the intake ports. Exhaust valves move between an opening position and a closing position of the exhaust ports. Camshafts actuate the intake and the exhaust valves. A hydraulic VVT mechanism changes an actuating timing of the camshaft at which the camshaft actuates the intake valves or the exhaust valves. An ECU controls the VVT mechanism based upon a control characteristic.

Abstract: A marine drive has an engine, a propeller and a transmission to switch the propeller between a propulsion position and a non-propulsion position. The engine has a combustion chamber. An air induction system communicates with the combustion chamber through an intake port. An exhaust system communicates with the combustion chamber through an exhaust port. Intake and exhaust valves move between an opening position and a closing position of the intake port and the exhaust port, respectively. Intake and exhaust camshafts actuate the intake and exhaust valves, respectively. A VVT mechanism changes an actuating timing of the intake camshaft at which the camshaft actuates the intake valve. An ECU controls the intake camshaft to set the actuating timing at a generally optimum timing. A transmission position change operation sensor senses that the transmission is under operation and sends a signal to the ECU.

Abstract: An air intake system for an engine of an outboard motor includes an air intake support member that provides support for other components of the air intake system. The other component of the air intake system that can be supported by the air intake support member include a throttle valve assembly, plenum chambers, and air intake passages. The air intake passages can be made longer to increase engine performance and can be manufactured with less material because the air intake passages do not need to provide support for the air intake system.

Abstract: An electronically controlled engine management system for adjusting camshaft timing, taking into account mechanical deficiencies of a variable camshaft timing mechanism and compensating the mechanical deficiencies by manipulating the amount and/or timing of the fuel injection. The engine management system enables the operator to enjoy high torque and good fuel efficiency representative of the compensated adjustable camshaft timing system.

Abstract: A direct fuel injector is positioned to provide better fuel atomization within the combustion chamber. The direct fuel injector is disposed between an intake manifold and a cylinder head assembly thereby eliminating the need for additional fuel delivery conduits, thus decreasing the size of the engine and lowering the production costs of the outboard motor. The direct fuel injector position permits immediate air/fuel mixture adjustments allowing improved acceleration enrichment and lean stratified charge operation. The direct fuel injector position and routing of induction system components allows for compact placement of auxiliary components. The integrated direct fuel injector position enables the operator to enjoy compact engine design, improved engine performance and increased fuel efficiency.

Abstract: A four-cycle engine for a marine drive includes an improved construction. The engine has an air induction device for introducing air to a combustion chamber. The air induction device defines an intake port next to the combustion chamber. An intake valve is movable between open and closed positions of the intake port. A valve actuator is journaled on the engine body for rotation to actuate the intake valve at a set angular position. A variable valve timing (VVT) mechanism is arranged to set the valve actuator to the angular position between advanced and delayed angular positions. A dedicated oil pump supplies pressurized oil to an oil control valve, which regulates and controls the VVT mechanism. A lubricant oil pump supplies pressurized oil to an engine lubrication system.

Abstract: An engine for a marine drive has a combustion chamber. An engine body of the engine defines an air intake port communicating with the combustion chamber. An air induction system communicates with the air intake port to introduce air to the combustion chamber through the air intake port. An exhaust system communicates with the combustion chamber through an exhaust port. Intake and exhaust valves move between an opening position and a closing position of the intake port and the exhaust port, respectively. Intake and exhaust camshafts actuate the intake valve and the exhaust valve, respectively. A VVT mechanism is associated with at least one of the camshafts and changes an actuating timing of the camshaft. The VVT mechanism includes a solenoid actuator that varies a hydraulic flow in the VVT mechanisms to change the actuating timing of the camshaft. The solenoid actuator can be operated to receive electric power from a power source. An ECU controls the solenoid actuator based upon a control characteristic.

Abstract: An internal combustion engine comprising an engine body. A combustion chamber is formed in the engine body and has at least one valve seat. A valve is configured to move between an open position and a closed position of the valve seat. A valve actuator is configured to actuate the valve. A variable valve timing mechanism is configured to change an actuating timing of the valve actuator at which the valve actuator actuates the valve. At least one sensor configured to sense and operational condition of the engine. A control device is configured to determine if the engine is operating in a cruising mode. The control device is also configured to reduce engine speed fluctuations during the cruising mode by adjusting the actuating timing of the valve actuator.

Abstract: An outboard motor includes four-cycle engine for a marine drive, and more particularly a four-cycle engine for a marine drive that has a vertically extending camshaft. The four-cycle engine includes at least one pre-ignition or knock sensor. An electronic control unit adjusts ignition timing and intake camshaft timing to protect the engine during a pre-ignition condition while improving fuel efficiency and preserving high engine output.

Abstract: An internal comustion engine has an air induction system that provides an intake passage and an intake silencer, wherein there are a plurality of openings between the silencer and the intake passage. The openings can be selectively closed so as to effectively lengthen or shorten the flow path through the intake passage. upstream portions of the intake passage are disposed within the intake silencer so as to facilitate compactness of the induction system. The openings are closed during low and medium engine speeds, and are opened during high engine speeds.

Abstract: An engine has a crankshaft journaled on an engine body. The crankshaft has an end portion that extends outward beyond the engine body. In some embodiments, a flywheel has a hub portion and a wheel portion which are unitarily formed with each other. The hub portion has a cylindrical shape that extends generally along an axis of the crankshaft and is coupled with the end portion of the crankshaft. The hub portion has a uniform thickness and a nut or bolt fastens the hub portion onto the end portion of the crankshaft. In other embodiments, the flywheel has a wheel portion and a coupling portion which are unitarily formed with each other. The coupling portion extends over the end portion of the crankshaft and intersects an axis of the crankshaft. Multiple bolts fasten the coupling portion onto the end portion of the crankshaft.

Abstract: A propulsion system for a watercraft includes an engine. An air intake device delivers air to a combustion chamber. A throttle valve regulates an amount of the air. A control device sets the throttle valve to a desired position. A remote controller provides the control device with the desired position. The engine can include an auxiliary intake device that delivers supplemental air to the combustion chamber. A control valve normally shuts the supplemental air from the combustion chamber. The control device determines whether an abnormal condition occurs in setting the throttle valve to the desired position. The control device determines whether the amount of the air is insufficient. The control device controls the control valve to allow the supplemental air to move to the combustion chamber when the control device determines that the abnormal condition occurs and the amount of the air is insufficient.