Abstract: In an outboard motor shift control system to change the shift position by controlling the supply of current to an electric shift motor for driving a shift mechanism, a detent mechanism is equipped for constraining the operation of the shift mechanism and holding the shift position once the shift position has been established, and the supply of current to the shift motor is discontinued upon detection that the shift position has been established. This configuration makes it possible to minimize the power consumption of the shift motor and ensure secure holding of the established shift position.

Abstract: In an outboard motor steering control system having a plurality of outboard motors each adapted to be mounted on a stern of a boat by a shaft to be movable by an actuator relative to the boat and each having an internal combustion engine to power a propeller, a desired steering angle of each outboard motor is determined individually based on detected engine speed and rotation angle of a steering wheel, and the operation of the actuator is controlled based on the determined desired steering angle, thereby improving both straight course-holding performance and turning performance by regulating the relative angles between the outboard motors in response to the cruising conditions of the boat.

Abstract: In an outboard motor steering control system having an actuator steering the outboard motor, three rotation angle sensors each detecting a rotation angle of a steering wheel, three steering angle sensors each detecting a steering angle of the outboard motor, and a controller determining a drive current to be supplied to the actuator based on the detected rotation angle and steering angle and supplies the current to the actuator to control its operation, the steering angle is estimated based on the current and a detected engine speed, and the controller determines the current based on the detected rotation angle and the estimated steering angle, when all of the steering angle sensors are detected to have failed, thereby enabling steering of the outboard motor to be continued even when the steering angle sensors have all failed.

Abstract: In an outboard motor control system having two outboard motors each mounted on a stern of a boat, there is provided a controller that controls operation of steering actuators to regulate steering angles of the outboard motors such that lines extending from axes of rotation of the propellers of the outboard motors intersect at a desired point. With this, it becomes possible to freely adjust the stream confluence point of the outboard motors, thereby improving boat driving stability and providing enhanced auto-spanker performance.

Abstract: In an outboard motor shift control system having a shift mechanism including a forward gear, a reverse gear and a clutch and an electric motor moving the clutch to engage with one of the forward and reverse gears or to disengage it therefrom, current supplied to the motor is detected, and completion of shift change is discriminated based on the detected current. With this, it becomes possible to detect completion of the shift change accurately, without being affected by shift mechanism aging and manufacturing variances.

Abstract: In an outboard motor steering system, the engine speed is detected as a value indicative of the speed of the boat and a current value for operating a steering hydraulic cylinder is determined to decrease with decreasing engine speed. The current value can therefore be determined in accordance with the steering load to reduce electric power consumption. Moreover, owing to the fact that the drive current is determined as a function of steering load, it is possible to prevent the output of the cylinder from becoming excessive relative to the steering load, thereby ensuring that the steered angle tracks a desired steering angle with good accuracy.

Abstract: A remote operation system for an outboard motor includes a remote control box installed at a cockpit of the boat and a lever attached to a support shaft that is rotatably accommodated in the remote control box for being manipulated by an operator, a plurality of sensors, such as a potentiometer and a rotary encoder provided to generate outputs indicative of an angle of rotation of the support shaft through the lever manipulation, respectively, and a control unit which controls operation of a throttle actuator and a shift actuator based on at least one of the outputs of the sensors, thereby improving reliability and enabling continued regulation of throttle opening and change of shift position even if a failure occurs in one of sensors.

Abstract: In an outboard motor exhaust system having a first exhaust gas passage discharging engine exhaust gas into water and a shift actuator operating a shift mechanism to establish one from among a forward position, a reverse position and a neutral position, there are provided a second exhaust gas passage branched from the first exhaust gas passage at a location above the water and an exhaust valve installed in the second exhaust gas passage and connected to the shift mechanism to be opened when the reverse position is established. The exhaust valve is alternatively opened by an exhaust valve actuator installed separately from the shift actuator. With this, it becomes possible to prevent the decrease in thrust produced during reverse boat travel by the engine exhaust gas being sucked in by a propeller, without degrading shift feel.

Abstract: In a boat having a seat, a steering wheel, and an outboard motor, an outboard motor steering system is provided, where the steering wheel is installed near the seat a steering angle sensor installed near the steering wheel for outputting a signal indicative of a steering angle of the steering wheel. The steering system also includes a swivel shaft connected to a propeller to turn the propeller relative to the boat, and an electric motor connected to the swivel shaft for rotating the swivel shaft in response to the detected steering angle. The steering system also includes a manipulation load regulation mechanism, such as a hydraulic damper, to produce an added load for increasing a manipulation load of the steering wheel, thereby enabling reduced operator load by using the electric motor to steer the outboard motor, while improving the operator's feel of steering wheel manipulation.

Abstract: An outboard motor engine speed control system includes two outboard motors, sensors which detect a travel speed of the boat and the engine speeds of the outboard motors, and a controller which controls the engine speeds of the outboard motors to be synchronized with a highest one of the detected engine speeds when the boat travel speed is equal to or higher than a predetermined value, while controlling the engine speeds of the outboard motors to be synchronized with a lowest one of the detected engine speeds when the boat travel speed is lower the predetermined value. The operations involved in engine speed control of the outboard motors mounted on the boat are thereby simplified and the feel of operation is enhanced.