Abstract: An axis line of a cylinder and a cylinder head of a four-stroke engine is disposed inclining to one side in a lateral direction with respect to a center line extending in a front-rear direction of the outboard motor from a top view, and a fuel tank is disposed on a side portion of the cylinder and the cylinder head in another side in the lateral direction with respect to the center line.

Abstract: An axis line of a cylinder and a cylinder head of a four-stroke engine is disposed inclining to one side in a lateral direction with respect to a center line extending in a front-rear direction of the outboard motor from a top view, and a fuel tank is disposed on a side portion of the cylinder and the cylinder head in another side in the lateral direction with respect to the center line.

Abstract: In a moving center estimation method, a provisional moving center is set at a predetermined position in a neighborhood of an actual moving center of a hull. A sample thrust having a predetermined magnitude and direction is applied to the provisional moving center by driving the outboard motor, and a magnitude and direction of an angular acceleration generated in the hull by application of the sample thrust is detected. The magnitude of the angular acceleration is compared with a predetermined threshold value, and a position of the provisional moving center is changed and set so that the angular acceleration may converge in the threshold value, when the angular acceleration is larger than the threshold value.

Abstract: An axis line of a cylinder and a cylinder head of a four-stroke engine is disposed inclining to one side in a lateral direction with respect to a center line extending in a front-rear direction of the outboard motor from a top view, and a fuel tank is disposed on a side portion of the cylinder and the cylinder head in another side in the lateral direction with respect to the center line.

Abstract: In a control device for outboard motors that controls two outboard motors attached to a boat, according to an operation by an operating lever that is tiltable in all directions from a neutral state, when the operating lever is moved to a different zone, a steering control unit controls shift positions of the two outboard motors and a steering specification according to a zone to which the operating lever is moved first, until a determination unit determines that the operating lever is in the neutral state, thereby enabling steering easily reflecting the intention of a boat operator and improving a steering efficiency even when an operation of moving from zone to zone is performed.

Abstract: In a moving center estimation method, a provisional moving center is set at a predetermined position in a neighborhood of an actual moving center of a hull, a sample thrust having a predetermined magnitude and direction is applied to the provisional moving center by driving the outboard motor, a magnitude and direction of an angular acceleration generated in the hull by application of the sample thrust is detected, the magnitude of the angular acceleration is compared with a predetermined threshold value, and a position of the provisional moving center is changed and set so that the angular acceleration may converge in the threshold value, when the angular acceleration is larger than the threshold value.

Abstract: A boat operating system has two outboard motors and a helm controller. The helm controller moves the boat in parallel in a lateral direction by performing steering so that extended lines of propulsive forces of the two outboard motors pass a movement center located on a center line of the boat, and causing shift directions of the two outboard motors to be reversed from each other, judges whether or not the boat is turning in a horizontal direction, and moves an intersection of the extended lines of propulsive forces of the two outboard motors and the center line of the boat in a direction of either forward or backward from the movement center when it is judged that the boat is turning while the boat is moved in parallel in the lateral direction.

Abstract: In a control device for outboard motors that controls two outboard motors attached to a boat, according to an operation by an operating lever that is tiltable in all directions from a neutral state, when the operating lever is moved to a different zone, a steering control unit controls shift positions of the two outboard motors and a steering specification according to a zone to which the operating lever is moved first, until a determination unit determines that the operating lever is in the neutral state, thereby enabling steering easily reflecting the intention of a boat operator and improving a steering efficiency even when an operation of moving from zone to zone is performed.

Abstract: A reset system for a watercraft outboard engine comprises: a control unit comprising a time summating portion for summating time for management of oil change time of an engine, a memory portion having a non-volatile memory such as an EEPROM for memorizing the cumulative time when the engine remains off and a determining portion for determining whether the cumulative time exceeds a set time by comparing the stored cumulative time with the set time; a warning portion for giving warning based on the comparison result when the cumulative time exceeds the set time; and a reset information entry portion for permitting reset information for clearing memory of the cumulative time in the memory and setting it into the initial value. The reset system can make control of the watercraft outboard engine based on the cumulative time.

Abstract: In an engine having an intake device provided with a solenoid valve, an amount of intake air is controlled on a basis of a duty control by means of a control unit, and the control unit includes an element for recognizing a state which is evidently different from a normal state to thereby stationarily hold a duty of the solenoid valve at a necessary set value.

Abstract: A water-cooled multi-cylinder engine, includes a control system in which an engine revolution number is reduced to a level less than a restriction revolution number on the basis of at least one condition of misfire and fuel stop for all the cylinders of the engine, at a time of an occurrence of an overheat, so as to restrict an increasing of a temperature of the engine. In a case when the engine revolution number is less than the restriction revolution number after the overheat occurs, or the engine revolution number is lowered to be less than the restriction revolution number on the basis of the revolution number restriction control, a specific cylinder is controlled to be stopped by at least one of misfire and fuel stop.

Abstract: A reset system for a watercraft outboard engine comprises: a control unit made up of a time summating portion for summating time for management of oil change time of an engine, a memory portion having a non-volatile memory such as an EEPROM for memorizing the cumulative time when the engine remains off and a determining portion for determining whether the cumulative time exceeds a set time by comparing the stored cumulative time with the set time; a warning portion for giving warning based on the comparison result when the cumulative time exceeds the set time; and a reset information entry portion for permitting reset information for clearing memory of the cumulative time in the memory means and setting it into the initial value. The reset system can make control of the watercraft outboard engine based on the cumulative time.

Abstract: An outboard motor has an engine in which a crankshaft is disposed perpendicularly, a flywheel is disposed to an upper end portion of the crankshaft to be rotatable in unison with the crankshaft and the flywheel is provided with a detecting member a motion of which is detected by a sensor means for detecting a detecting number of revolution and a revolution angle of the crankshaft. The detecting member is disposed in an axial direction of the crankshaft.

Abstract: A water-cooled multi-cylinder engine, includes a control system in which an engine revolution number is reduced to a level less than a restriction revolution number on the basis of at least one condition of misfire and fuel stop for all the cylinders of the engine, at a time of an occurrence of an overheat, so as to restrict an increasing of a temperature of the engine. In a case when the engine revolution number is less than the restriction revolution number after the overheat occurs, or the engine revolution number is lowered to be less than the restriction revolution number on the basis of the revolution number restriction control, a specific cylinder is controlled to be stopped by at least one of misfire and fuel stop.

Abstract: In an engine having an intake device provided with a solenoid valve, an amount of intake air is controlled on a basis of a duty control by means of a control unit, and the control unit includes an element for recognizing a state which is evidently different from a normal state to thereby stationarily hold a duty of the solenoid valve at a necessary set value.

Abstract: A water jacket device for an outboard motor is designed to accommodate electrical components and improve cooling efficiency. The water jacket device has a base portion, and a cover portion hermetically coupled to the base portion for retaining a fluid between the base portion and the cover portion. The cover portion has an portion integrally formed with the cover portion, for installing an electrical component so that the electrical component is configured to be cooled by the fluid.

Abstract: An outboard motor has an engine in which a crankshaft is disposed perpendicularly, a flywheel is disposed to an upper end portion of the crankshaft to be rotatable in unison with the crankshaft and the flywheel is provided with a detecting member a motion of which is detected by a sensor means for detecting a detecting number of revolution and a revolution angle of the crankshaft. The detecting member is disposed in an axial direction of the crankshaft.

Abstract: An engine running control apparatus includes a full-closure state detecting device for outputting a full-closure detection signal when the throttle valve is in the fully closed state, a control device for controlling the open degree of the air control valve, a time-measuring device for counting up a predetermined period of time in response to the full-closure detection signal, an engine speed detecting device for detecting the rotating speed of the engine and an initial value setting device for setting up an engine speed at which control of the degree of the opening is started by the control device, in response to the full-closure detection signal.

Abstract: An alarm device of an outboard motor arranged in operative association with an engine thereof to which a sensor device including a plurality of sensors is mounted and operated by a control power source, comprises a central control device into which an operation condition of the engine is inputted, a sensor trouble judging device connected to the central control device and the sensor device for judging a state of trouble of the sensor device, an alarm control device, a sound alarm device controlled by the alarm control device, and an alarm judging device for judging a type of an alarm, which is connected to the alarm control device so as to operate the alarm control device to operate the sound alarm device in response to an information from the sensor trouble judging device.

Abstract: A warning system for an outboard motor, includes: an oil-pressure switch for outputting the low-pressure state signal when the oil pressure of the lubricating oil lowers than a fixed reference pressure; a control device for controlling the operation of the warning device; a determining device which judges whether the low-pressure state signal continues to be output longer than the predetermined delay time and determines that the oil pressure is abnormal if the judgment is affirmative; and a control device for actuating the warning device so as to perform a warning operation when the determining device has determined that the oil pressure is abnormal.