Abstract: An outboard motor can comprise a cowling for covering an engine, a high pressure fuel supply system, and a low pressure fuel supply system. The high pressure fuel supply system can have a vapor separator tank and a high pressure fuel pump. The low pressure fuel supply system can have a low pressure fuel pump. A heat insulating chamber, defined from a space for accommodating the engine, can be formed within the cowling. The heat insulating chamber houses the low pressure fuel pump and the fuel filter.

Abstract: A watercraft is controllable by either a main station or a substation. A main-side remote control device is disposed in the main station. A sub-side remote control device is disposed in the substation. An outboard motor for generating propulsion force is controlled by the main-side remote control device or the sub-side remote control device. The sub-side remote control device is connected to the main-side remote control device by wiring, and the main-side remote control device is connected to the outboard motor by a network.

Abstract: An engine failure diagnosis system simply performs failure diagnosis of engine components, which are driven while an engine is operating, even at the time when the engine is stopped, and identifies a component that has failed and a location where a failure has occurred. The engine failure diagnosis system includes an ECM arranged to control an engine provided in an outboard motor of a watercraft. The ECM includes an actuation command section arranged to actuate engine components, which are driven while the engine is running, in a given manner, and a failure diagnosis section arranged to diagnose the presence of a failure in the engine components. The engine components of the engine are provided with actuated condition detecting sections arranged to detect a predetermined actuated condition. When the actuation command section outputs an actuation command while the engine is stopped, the engine components are actuated in a given manner.

Abstract: A watercraft has an engine that is controlled to provide a slower operational watercraft speed during a reverse operation of the watercraft. The engine is controlled by detecting a reverse operation and an operator engine torque request. An operational characteristic of the engine (e.g., engine speed) is adjusted to decrease the engine output by a predetermined amount after it is determined that the watercraft is in reverse operation.

Abstract: A control device for propulsion units is adapted to synchronize the engine rotational speeds of a plurality of propulsion units arranged in a row on a vessel and operatively and electrically connected to two control levers that are positioned adjacent to each other. The control device synchronizes the engine rotational speeds by correcting the throttle opening of a target propulsion unit or units based on a deviation between the engine rotational speed of a reference propulsion unit and the engine rotational speed of the target propulsion unit. Upon cancellation of synchronization, the throttle opening correction is reduced stepwise from its corrected throttle opening to its natural throttle opening based on the position of the corresponding control lever. As such, large fluctuations in engine speeds are avoided upon cancellation of synchronization.

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: To enable smooth, highly accurate deceleration in various usage conditions of an outboard motor and realize stabilized engine speed after deceleration, a fuel controller for controlling the amount of fuel fed to an engine of an outboard motor mounted on a boat includes a deceleration determining section arranged to determine deceleration of the boat, an engine speed detecting section arranged to detect the engine speed of the engine, an engine load detecting section arranged to detect the load on the engine, and a controller arranged to control the amount of fuel fed to the engine when the boat is in deceleration according to the detected engine speed and engine load.

Abstract: A propeller thrust transmission device for a watercraft propulsion device prevents an occurrence of a precession of a spacer on an entire circumference around a taper part if a water resistance force acts upward on a propeller. The propeller thrust transmission device includes a taper part of an outer shaft part of a propeller shaft that is fitted in a spacer divided into a first half and a second half. A thrust force acting on a propeller is received by the taper part of the propeller shaft via the spacer. The first half includes a taper hole whose surface is contra-positive to the taper part and in which the taper part is fitted.

Abstract: An exhaust gas cooling system for an engine includes an exhaust gas conduit having an inner tube defining an exhaust gas passage and an exhaust coupler surrounding the inner tube and defining a cooling water passage together with the inner tube therebetween, and a water-lock coupled with a downstream end of the exhaust gas conduit through an exhaust gas conduit coupling section which extends from an upstream end of the water-lock. The exhaust gas conduit coupling section and the exhaust coupler are coupled with each other and the inner tube extends into the interior of the water-lock. A downstream end part of the inner tube can be formed to be a wide portion having a bell mouth configuration. A diameter of the downstream end part becomes larger as a portion thereof exists closer to the end of the downstream end part. The exhaust gas cooling system for the engine can be provided for a water vehicle.

Abstract: A sealing structure of an outboard motor comprises: a bottom cowling 11 covering a lower part of an engine 102; a top cowling 12 covering an upper part of the engine 102; and a sealing material 30 through which said top cowling 12 is attached to said bottom cowling 11, a bottom end 12a of said top cowling 12 being installed on an outer side of a top end 11a of said bottom cowling 11, wherein said sealing material 30 comprises: a cross-section roughly reversed U-shaped installation base member 31 fitted on the bottom cowling 11 by having the top end 11a of the bottom cowling 11 inserted in an opening thereof, a hollow seal member 32 which is fitted on an outer wall of the installation base member 31 and makes an elastic contact with an inner surface of the bottom end 12a of the top cowling 12; and a lip 33 projecting outward from the hollow seal member 32 and of which an upper surface makes an elastic contact with a bottom surface of the bottom end 12a of the top cowling 12.

Abstract: An outboard motor has a construction in which the area of an exhaust passage can be secured easily and exhaust noise is less likely to escape into the air, allowing the exhaust noise to be lowered. The outboard motor includes a lower case, a propeller shaft rotatably supported in the lower case, a propeller fixed to the propeller shaft, an engine, and a power transmission mechanism through which a driving force from the engine is transmitted to the propeller shaft to rotate the propeller. An exhaust case is provided in the lower case. The exhaust case includes an upper exhaust passage above the propeller shaft, the upper exhaust passage directing therethrough an exhaust gas from the engine, an exhaust outlet which is open in a rearward direction of the propeller shaft, and a communication exhaust passage arranged to communicate the upper exhaust passage with the exhaust outlet.

Abstract: A method for setting screens of plural inboard indicators connected to an inboard network via a communication line includes connecting a terminal to the inboard network. The method also includes loading the terminal with data from the plural indicators and setting the screens of the indicators in the terminal. Additionally, the method includes sending screen setting data from the terminal to the respective indicators via the communication line after setting the screens of the indicators.

Abstract: A throttle opening controller for one embodiment of a small planing boat includes: a throttle valve for changing the degree of opening in response to displacement of a throttle lever; a remaining fuel amount detector; a fuel consumption calculating means; and a throttle opening limiting means. In one embodiment, when a remaining fuel amount detected by the remaining fuel amount detector is equal to or below a preset value L1, the fuel consumption calculating means starts calculating total fuel injection amount. When a value, obtained by subtracting the total fuel injection amount from the preset value L1, is equal to or below a threshold L0, the throttle opening limiting means determines the degree of opening of the throttle valve based on an opening rate (k). An internal space of a fuel tank can be divided using a vertical partition into plural chambers. In addition, a knock sensor can be provided for an engine.

Abstract: An oil supplying apparatus for supplying the oil to an engine of a watercraft can be provided with an oil sump, a vapor-liquid separation chamber, a scavenging pump for sending the oil in the oil sump to the vapor-liquid separation chamber, a transfer path for returning the oil from which air and blow-by gas have been separated in the vapor-liquid separation chamber to the oil sump, a feed pump for supplying the oil in the oil sump to the engine, and openings and for returning oil used to lubricate the engine to the oil sump. The oil sump can be provided below the crankcase, and the vapor-liquid separation chamber can be provided to a side surface of the engine.

Abstract: A watercraft steering device can include at least one of steerage status detection device configured to detect a steerage status following an operation of the steering wheel, running status detecting device configured to detect a running status of the watercraft, watercraft propulsion unit status recognition device configured to recognize a status of an outboard motor such as an installation number thereof, and electric motor status detection device configured to detect a status of an electric motor, and can further include a lower unit turning force characteristic computation device configured to compute a lower unit turning force characteristic based on a detection value from at least one of the device, and an ECU configured to control at least one of a reaction force to the steering wheel, a limit lower unit turning angle, and a propulsive force based on a computed lower unit turning force characteristic and/or selecting the electric actuator to operate.

Abstract: A steering wheel, operable by an operator, can be electrically connected to an electric motor to provide an actuation signal corresponding to the amount of a steering wheel operation to the electric motor, a reaction motor for applying a reaction to the steering wheel, and an ECU for controlling the electric motor are provided. The ECU can include at least one of an operation status detection device for detecting an operation status corresponding to the steering wheel operation, a running status detection device for detecting a running status of the watercraft, an outboard motor status recognition device for recognizing a status of the outboard motor, such as the installation number thereof, and an electric motor status detection device for detecting a status of the electric motor.

Abstract: A watercraft can have an electric motor mounted on a screw bar extending in a right/left direction. The electric motor can move along the screw bar in the right/left direction to steer an outboard motor, or another part of a different marine propulsion system. One or more springs can be provided at the ends of the screw bar. When the outboard motor whose steered angle exists in a predetermined angle range including the maximum steered angle is steered back to a neutral position, either one of the springs presses the electric motor toward the center of the screw bar to assist the steering torque of the electric motor.

Abstract: A boat has a propulsion unit and a steering system. The steering system includes a steering device actuated by an electric actuator. A steering wheel operated by an operator is electrically connected to the actuator. Detectors collect data regarding one or more of operation status of the steering wheel, running status of the boat, status of the propulsion unit, status of the electric actuator, and the like. In certain situations, the electric actuator may not be capable of providing a quick steering response. A controller weighs detected data to identify such situations and controls a propulsive force of the propulsion unit so as to restrain the propulsive force if necessary to maintain good steering response.

Abstract: A method of plastically forming splines on a shaft-like workpiece is provided. The volume of part of the shaft-like workpiece on which the splines are plastically formed is generally the same as the volume of plastically processed portion following processing. In addition, the part on which the splines are formed first is made with a maximum diameter. The shaft-like workpiece extends from the first formed part toward the part that is not plastically processed in a conical shape.