Abstract: An engine body of the multiple-cylinder engine for an outboard motor can include a crankcase for supporting a crankshaft whose axis extends vertically, and plural cylinders that are vertically arranged in line, each cylinder horizontally extending outward from the crankcase, and each cylinder having a respective exhaust port formed in a cylinder head. There are can be provided plural exhaust passages, each passage extending from the downstream end of the exhaust port, each passage communicating with the exhaust port and expansion chambers. Each expansion chamber can communicate with the extending end of the exhaust passage.

Abstract: A marine engine is arranged such that it compares a detected ion current value with a predetermined sea water-ingress current value, which is indicative of sea water being present in the combustion chamber at the time of combustion.

Abstract: An outboard motor mounted to a hull of a watercraft includes a V-type engine having right and left cylinder banks positioned in a cowling and having a crankshaft generally vertically disposed when the watercraft is under a running condition. A surge tank is disposed in the cowling. Right and left side long intake conduits and right and left side short intake conduits both connect the surge tank to intake ports of respective right and left banks of cylinders. The associated long intake conduits and short intake conduits can be selectively established depending on information about operational conditions of the hull and/or the outboard motor. The outboard motor includes right and left shut-off valves interchanging the long intake conduits and the short intake conduits. Right and left actuators individually actuate the right and left shut-off valves in accordance with information about operational conditions. A control means individually controls operations of the respective actuators.

Abstract: An outboard motor is mounted on a hull and has an engine disposed in an upright position in a cowling so that a crankshaft thereof extends generally vertically during cruising. An embodiment of the motor includes a first surge tank disposed on the opposite side of a cylinder head of the engine with respect to the crankshaft of the engine; long intake pipes that communicate with the first surge tank and an intake port of the engine; second surge tanks disposed between the long intake pipes and the engine for communicating with the first surge tank; short intake pipes provided in the midway of the long intake pipes on the engine side for communicating with the second surge tanks; and on-off valves for opening and closing the short intake pipes.

Abstract: A marine engine is arranged such that it compares a detected ion current value with a predetermined sea water-ingress current value, which is indicative of sea water being present in the combustion chamber at the time of combustion.

Abstract: An outboard motor mounted to a hull of a watercraft includes a V-type engine having right and left cylinder banks positioned in a cowling and having a crankshaft generally vertically disposed when the watercraft is under a running condition. A surge tank is disposed in the cowling. Right and left side long intake conduits and right and left side short intake conduits both connect the surge tank to intake ports of respective right and left banks of cylinders. The associated long intake conduits and short intake conduits can be selectively established depending on information about operational conditions of the hull and/or the outboard motor. The outboard motor includes right and left shut-off valves interchanging the long intake conduits and the short intake conduits. Right and left actuators individually actuate the right and left shut-off valves in accordance with information about operational conditions. A control means individually controls operations of the respective actuators.

Abstract: An outboard motor is mounted on a hull and has an engine disposed in an upright position in a cowling so that a crankshaft thereof extends generally vertically during cruising. An embodiment of the motor includes a first surge tank disposed on the opposite side of a cylinder head of the engine with respect to the crankshaft of the engine; long intake pipes that communicate with the first surge tank and an intake port of the engine; second surge tanks disposed between the long intake pipes and the engine for communicating with the first surge tank; short intake pipes provided in the midway of the long intake pipes on the engine side for communicating with the second surge tanks; and on-off valves for opening and closing the short intake pipes.

Abstract: An outboard motor can be mounted on a transom plate of a hull, and can have an engine disposed in an upright position in a cowling so that a crankshaft thereof extends generally vertically during cruising. A surge tank can be located on the hull side of the engine in the cowling, and a mounting portion for an electric component can be provided on a front face of the surge tank.

Abstract: An engine body of the multiple-cylinder engine for an outboard motor can include a crankcase for supporting a crankshaft whose axis extends vertically, and plural cylinders that are vertically arranged in line, each cylinder horizontally extending outward from the crankcase, and each cylinder having a respective exhaust port formed in a cylinder head. There are can be provided plural exhaust passages, each passage extending from the downstream end of the exhaust port, each passage communicating with the exhaust port and expansion chambers. Each expansion chamber can communicate with the extending end of the exhaust passage.

Abstract: An engine air intake device for an outboard motor includes a plurality of main intake pipes corresponding to each cylinder. First and second branch pipes extend from an upstream end of each main part. The first branch pipes are longer than the second branch pipes. The second branch pipes each include a valve and are selectively closed. The first branch pipes open into a first surge tank. The second branch pipes open into a second surge tank that is formed separately from the first surge tank. In operation, the valves of the second branch pipes are open when the engine is operating in high engine speed and are closed at low-to-medium speeds.

Abstract: A system for replenishing a lubricant pan with the lubricant comprises a lubricant tank provided separately from the lubricant pan. A lubricant replenishing pump is provided in the lubricant tank for replenishing the lubricant pan with the lubricant. A lubricant level sensor is adapted to detect the lubricant level in the lubricant tank upon a main switch of an engine being turned on. The lubricant replenishing pump is operated according to the detected lubricant level to replenish the lubricant pan with a specified replenishing amount of the lubricant from the lubricant tank.

Abstract: An engine air intake device for an outboard motor includes a plurality of main intake pipes corresponding to each cylinder. First and second branch pipes extend from an upstream end of each main part. The first branch pipes are longer than the second branch pipes. The second branch pipes each include a valve and are selectively closed. The first branch pipes open into a first surge tank. The second branch pipes open into a second surge tank that is formed separately from the first surge tank. In operation, the valves of the second branch pipes are open when the engine is operating in high engine speed and are closed at low-to-medium speeds.

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 device communicates with the air intake port to introduce air to the combustion chamber through the air intake port. The air induction device includes a throttle valve to regulate an amount of the air. An air intake valve moves between an opening position and a closing position of the intake port. A camshaft actuates the intake valve. A VVT mechanism changes an actuating timing of the camshaft at which the camshaft actuates the intake valve. A control device controls the change mechanism. A throttle position sensor, an intake pressure or other sensors sends respective signals to the control device. The control device determines a sudden acceleration state of the engine based upon at least one of the signals.

Abstract: A system for replenishing a lubricant pan with the lubricant comprises a lubricant tank provided separately from the lubricant pan. A lubricant replenishing pump is provided in the lubricant tank for replenishing the lubricant pan with the lubricant. A lubricant level sensor is adapted to detect the lubricant level in the lubricant tank upon a main switch of an engine being turned on. The lubricant replenishing pump is operated according to the detected lubricant level to replenish the lubricant pan with a specified replenishing amount of the lubricant from the lubricant tank.

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 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 fuel supply system for an outboard motor regulates the fuel pressure to a vapor separator in a fuel injection system by using a pressure relief valve that returns excess fuel to the intake of the fuel pump. In order to permit excess fuel flow without substantial excess at low speeds, the fuel pump speed is regulated depending upon engine speed, fuel temperature, and fuel pressure.

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 device communicates with the air intake port to introduce air to the combustion chamber through the air intake port. The air induction device includes a throttle valve to regulate an amount of the air. An air intake valve moves between an opening position and a closing position of the intake port. A camshaft actuates the intake valve. A VVT mechanism changes an actuating timing of the camshaft at which the camshaft actuates the intake valve. A control device controls the change mechanism. A throttle position sensor, an intake pressure or other sensors sends respective signals to the control device. The control device determines a sudden acceleration state of the engine based upon at least one of the signals.

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.