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 camshaft cover member encloses the camshaft together with an engine body of the engine. The camshaft cover member defines a slot through which a tool can pass. The tool can prevent the camshaft from rotating.

Abstract: An integrated fuel delivery system is cooled by induction air providing a higher density air/fuel mixture to fuel injectors. The fuel delivery system is integrated within an intake passage body 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 integrated fuel delivery system enables the operator to enjoy compact engine design, improved engine performance and increased fuel efficiency.

Abstract: An engine has an engine body having an outer surface that defines an outer area next thereto. An air intake system has an intake valve movable between a closed position and an open position. An intake camshaft that actuates the intake valve extends through the engine body and toward the outer area beyond the outer surface. A drive mechanism drives the camshaft. A portion of the drive mechanism is disposed in the outer area. A hydraulically operated change mechanism changes an angular position of the camshaft relative to a crankshaft. A control valve unit controls the change mechanism. The control valve unit at least in part is disposed within the outer area.

Abstract: An air induction system for an engine is provided with a flow meter to sense a flow amount of air introduced into a combustion chamber of the engine. The air induction system includes an improved construction that can protect the flow meter from rigorous environment. The construction includes a primary intake passage through which the air flows. A secondary intake passage extends from the primary passage to communicate with the primary passage. At least a portion of the air flows through the secondary passage. A filter is disposed in the secondary passage to filtrate the portion of the air. The flow meter is positioned downstream of the filter in the secondary passage.

Abstract: An outboard motor incorporates a driveshaft and a propulsion shaft driven by the driveshaft. The driveshaft carries a pinion. The propulsion shaft carries forward and reverse gears. The pinion always meshes with the forward and reverse gear and drives the forward and reverse gears in opposite directions relative to each other. A hydraulic forward clutch mechanism couples the forward gear with the propulsion shaft. A hydraulic reverse clutch mechanism couples the reverse gear with the propulsion shaft. A shift actuator selectively operates the forward clutch mechanism or the reverse clutch mechanism to provide forward, reverse and/or neutral running conditions for the outboard motor.

Abstract: A fuel supply for an internal combustion engine includes an improved construction for inhibiting vapor from appearing in the fuel supplied to the engine's combustion chamber(s). A fuel injector, as one of fuel supply devices, is provided for supplying fuel to the combustion chamber of the engine. There are a first and second fuel reservoirs. The first fuel reservoir stores fuel and delivers it to the second fuel reservoir through a first fuel supply conduit, while the second fuel reservoir temporarily store the fuel and delivers it to the fuel injector through a second fuel supply conduit. The excess fuel is returned to the second fuel reservoir from the fuel injector through a fuel return conduit. The fuel supply includes a fuel cooling device for cooling the fuel passing through at least one of the conduits. The construction of the fuel supply and the fuel cooling device permits them to be located with the tight confines between the engine and a protective enclosure (e.g.

Abstract: An engine includes an engine body and four pistons reciprocally moveable relative to the engine body. The engine body and the pistons together define four combustion chambers. An air induction system is arranged to introduce air into the combustion chambers. The air induction system includes four intake passages corresponding to the respective combustion chambers. A plenum chamber is coupled with the intake passages. The air is delivered to each combustion chamber from the plenum chamber through each intake passage in due order. The plenum chamber is divided into first and second sub-chambers. The intake passages are categorized into first and second groups. Each group includes two of the intake passages which have discontinuity in the order with each other. The first group is connected with the first sub-chamber. The second group is connected with the second sub-chamber.

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 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: An engine includes an air induction system, a fuel supply system, a lubrication system and a ventilation system. The fuel supply system has a fuel reservoir in which a space for fuel vapors is defined. The lubrication system lubricates a component of the engine with lubricant. The ventilation system couples a crankcase of the engine with the air induction system so as to deliver oil vapors in the crankcase to the air induction system. A fuel vapor passage is arranged to couple the space of the fuel reservoir with the ventilation system.

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 camshaft cover member encloses the camshaft together with an engine body of the engine. The camshaft cover member defines a slot through which a tool can pass. The tool can prevent the camshaft from rotating.

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: A throttle valve control mechanism for an internal combustion engine. In one feature of the invention, the engine has multiple cylinders extending generally horizontally, spaced vertically relative to each other. The engine also has an air induction system extending generally horizontally. The air induction system includes a plurality of air intake ducts each having a throttle valve. Each throttle valve has a throttle valve shaft extending generally vertically and linked together. A throttle valve control mechanism is provided. The throttle valve control mechanism has a throttle lever for rotating the throttle valve and the throttle lever is movable in a plane existing generally horizontally. Almost of the other part of the throttle valve control mechanism is movable in a plane existing generally vertically. If the engine is mounted on an outboard motor and encircled by a protective cowling, the other part of the throttle valve control mechanism is placed between the engine and the protective cowling.

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: An integrated fuel delivery system is cooled by induction air providing a higher density air/fuel mixture to fuel injectors. The fuel delivery system is integrated within an intake passage body 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 integrated fuel delivery system enables the operator to enjoy compact engine design, improved engine performance and increased fuel efficiency.

Abstract: An engine for an outboard motor includes engine components disposed around the engine body. A cooling system includes a first water passage cooling the engine body and a second water passage branching off from the first water passage upstream the engine body and extending through the engine components. One engine component is generally positioned above the engine body. Two engine components are positioned on different sides of the engine body. The first and second water passages have separate discharge ports. The engine components are made of a metal material. The second water passage is defined by tubular members made of a corrosion-resistant material and the respective tubular members are embedded in the respective bodies of the engine components.

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 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: 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: 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.