Abstract: A speed control system for a small planing boat can comprise a speed sensor to detect a vessel speed of a boat body, a speed information storing unit on which data of a previously set maximum speed limit of the boat body is stored, and a speed control device for controlling the cruising speed of the boat body not to exceed the maximum speed limit based on a result of a correlation between the cruising speed and the maximum speed limit. The speed control device can comprise a revolution speed sensor, a revolution speed acquiring unit and a revolution speed control unit. The speed control device can also work in conjunction with an intake air mass amount control device which can include an electronically-controlled throttle valve, an air mass amount acquiring unit and a throttle opening degree control unit.

Abstract: A remote control system for controlling a propulsion unit of a watercraft includes a plurality of remote controller side ECUs, all of which have the same construction in one embodiment. Each remote controller side ECU includes ECU discriminating terminal sections and an ECU determining section for determining a role of each remote controller side ECU based upon signals provided by the ECU discriminating terminal sections. The ECU determining section determines a role of the particular remote controller side ECU based upon the signals provided by the ECU discriminating terminal sections when the remote controller side ECU starts operating. The ECU determining section also reads out the most proper one of first through sixth exclusive use sections, which define the function of the ECU's role. A determination result is stored in first, second and third EPROMs so as to be used to determine the role.

Abstract: An oil supply device includes an axial oil passage and an intersecting oil passage provided in a propeller shaft, an axial oil passage and an intersecting oil passage provided in a drive shaft, and an oil guide passage. The intersecting oil passages allow oil inside the axial oil passages to be spouted radially of the shaft by centrifugal force generated as the shafts rotate. The oil is then supplied via the oil guide passage to an intermediate speed reduction device. As a result, it is possible to sufficiently lubricate an intermediate speed reduction device mounted on a drive shaft through a simple and compact arrangement.

Abstract: A boat includes a steering load detector arranged to calculate an output value of a steering motor necessary for steering an outboard motor in a traveling state, a motor output detector arranged to detect a possible output value that can be output by the steering motor, a prediction determination unit arranged to compare the necessary output value from the steering load detector with the possible output value from the motor output detector, and an electric power load control unit arranged to perform a control operation so as to increase a battery charge amount and/or to reduce the electric power load when the necessary output value is determined to be larger than the possible output value. As a result, the boat that can effectively perform steering when a motor output becomes small as a result of a reduced battery charge amount.

Abstract: An outboard motor includes a transmission device disposed on a middle portion of a drive shaft driven by an engine. The transmission device includes a forward-reverse switching device housed in a transmission case. Lubricating oil for lubricating the forward-reverse switching device is stored in the transmission case. The transmission case has a drain hole arranged to discharge lubricating oil in the transmission case that is provided in a lower portion of a side wall and in a position in front of the drive shaft, and a drain bolt for opening or closing the drain hole. An exposed opening for exposing the drain hole is provided in an upper case that covers the transmission case. As a result, work efficiency in discharging or draining of lubricating oil is greatly improved without requiring dismantling of a main body of the outboard motor.

Abstract: A water cooling apparatus in a power transmission system of a boat propulsion system includes a transmission unit that changes the speed of an output from an engine and then transmits the output to a propeller shaft. The transmission unit includes a cylindrical transmission case with an axis extending vertically, a transmission device housed in the transmission case and arranged to change the speed of an input, and a cooling water passage formed in the transmission case for flowing cooling water. In the plan sectional view of the transmission unit, the cooling water passage is formed in at least one of a side portion or a rear portion of the transmission case. As a result, strain on a rear portion of a hull that supports a boat propulsion unit is prevented and minimized, while a transmission unit is sufficiently cooled with cooling water.

Abstract: In an outboard motor, a lower casing is located below an upper casing, and an engine with a vertically-arranged crankshaft is mounted above the upper casing. The rotation of the crankshaft is transmitted to a drive shaft pivotally supported in the upper casing, has its speed changed by a transmission mounted on the drive shaft, and is transmitted to a propeller shaft pivotally supported in the lower casing. The upper casing includes an upper-side casing and a lower-side casing, and mating surface portions of the upper-side casing and the lower-side casing are laterally wider than an upper section and a lower section of the upper casing.

Abstract: A boat propulsion system includes a control section, a thrust calculation section, a thrust generating unit, a thrust detection section, and a control section. An accelerator opening is input to the control lever by operation of an operator. The accelerator opening detection section detects the input accelerator opening. The thrust calculation section calculates a thrust intended to be generated from the accelerator opening to output a calculated thrust. The thrust generating unit generates a thrust. The thrust detection section detects a thrust actually generated on the thrust generating unit to output it as an actual thrust. The control section controls an output of the thrust generating unit so that the actual thrust approaches the calculated thrust.

Abstract: An outboard motor includes a lower casing provided below an upper casing, amounting plate provided above the upper casing, and an engine with a vertically-arranged crankshaft mounted on the mounting plate. The rotation of the crankshaft is transmitted to a drive shaft that is pivotally supported in the upper casing, changed in speed by a transmission mounted on the drive shaft, and transmitted to a propeller shaft that is pivotally supported in the lower casing. The outboard motor has upper mounts and lower mounts arranged to mount the outboard motor on a hull. The upper mounts are disposed on upper lateral surfaces of the upper casing, and the lower mounts are disposed on lower lateral surfaces of the upper casing. The outboard motor simplifies the upper casing for disposing a transmission therein and assembly and maintenance thereof.

Abstract: A cooling system includes a coolant distributing device arranged to distribute coolant discharged from a water pump to both an engine and a transmission device. The coolant distributing device includes a coolant relay section, an inlet conduit member, an outlet conduit member, and a transmission cooling conduit member, and supplies a portion of the coolant discharged from the water pump to a highest portion of a water jacket of the transmission device, and discharges the water from a lowest portion of the water jacket. The cooling system effectively cools the transmission device with a simple construction facilitating assembly and maintenance.

Abstract: An outboard motor includes a water pump arranged to draw in cooling water, a pump drive mechanism that decelerates rotation of a drive shaft and transmits the rotation to the water pump, and an oil supply device (a main oil passage, oil ejection passages, a hollow portion, and an oil ejection hole) arranged to supply oil to lubricate a transmission to the pump drive mechanism. The outboard motor is able to prevent occurrence of cavitation in a water pump of a vane-type pump and to increase a discharge amount of the pump while an engine is running at high speed.

Abstract: A motor including an intake-side conduit member disposed outside a casing that makes a connection between a cooling water intake section of a water pump and an intake hole, and a cooling water relay section provided outside the casing. The cooling water relay section communicates with a cooling water supply passage in the casing. A discharge-side conduit member that is disposed outside the casing connects the cooling water relay section to a cooling water discharge section of the water pump. Additionally, the other end of a transmission cooling conduit member that is branched from the cooling water relay section is connected to a water jacket of the transmission. The conduit members are preferably flexible hose members, for example. Accordingly, this unique construction improves a cooling water piping layout around a water pump, a discharge performance of the water pump, and an assembly workability of a motor.

Abstract: A shift-in operation determination device determines a shift-in operation based on a signal in accordance with an operation of a remote control lever. An ignition timing operation device retards an ignition timing of an engine based on a determination result of the shift-in operation by the shift-in operation determination device. A shift-in command device engages a shift actuator and a dog clutch with either of a forward traveling bevel gear or a rearward traveling bevel gear in a state where the ignition timing of the engine is retarded. The shift-in operation determination device works to prevent a shock which occurs at a shift-in while maintaining a stable engine output in an outboard motor.

Abstract: A water jet propulsion boat includes a fuel pump driven by an electric control unit and arranged to deliver fuel from a fuel tank to an engine via a fuel pipe, and a fuel pressure sensor arranged to detect a pressure of the fuel delivered to the engine by the fuel pump. When a magnitude of the fuel pressure detected by the fuel pressure sensor is less than a predetermined magnitude, the fuel pump is activated. On the other hand, when the magnitude of the fuel pressure detected by the fuel pressure sensor is equal to or greater than the predetermined magnitude, the fuel pump is deactivated. Also, when the fuel pressure detected by the fuel pressure sensor becomes equal to or less than an abnormal threshold value, either one or both of the fuel pump and the engine are deactivated. The water jet propulsion boat lowers power consumption, reduces battery size, extends battery life, and lowers costs.

Abstract: A small boat includes engines mounted on a hull, a plurality of water jet propulsion units disposed on both sides of a longitudinal axis of the hull and driven by the engines, and a steering wheel arranged to change jet directions of the water jet propulsion units. The small boat further includes a steering angle sensor arranged to detect a rotational angle of the steering wheel, front and rear gravity sensors arranged to detect a turning state of the hull, and a control device to which the rotational angle and the turning state of the hull are inputted in order to control thrusts of the water jet propulsion units such that the turning state coincides with any one of a group of target steady turning radii corresponding to the rotational angle of the steering wheel. The small boat turns along the steady radius regardless of any water conditions.

Abstract: An abnormality detection device of a fuel pump reduces costs and prevents detection error or breakdown by making the fuel pressure sensor unnecessary. The abnormality detection device includes an abnormality detection circuit, a fuel pump driving voltage detection unit to detect the voltage value of an abnormality detection circuit, and a meter. The abnormality detection circuit is constituted by the circuit including a resistance disposed between a battery side of the fuel pump motor to drive the fuel pump and a ground side. If the voltage value detected by the fuel pump driving voltage detection unit is larger than the upper limit or lower than the lower limit of the normal range, the warning lamp of the meter flashes and a buzzer makes an alarm sound. The abnormality detection circuit is housed in the fuel pump module disposed in the fuel tank.

Abstract: A water jet propulsion boat is constructed such that a fuel pressure detection device is free from a detection error or breakdown and a restart ability of an engine is protected against malfunction. A fuel tank is provided in a boat body of the water jet propulsion boat through vibration absorbing members. A fuel pump unit including a fuel pump is provided in the fuel tank. A fuel pressure sensor is provided in the fuel pump unit. An electric control device stops the fuel pump if the value detected by the fuel pressure sensor is out of the normal value range. Additionally, an electric control device stops operation of the fuel pump if the fall sensor detects the overturning of the boat body and if the detected value of the fuel pressure sensor is out of the normal value range. A regulator and a filter are provided to the fuel pump unit.

Abstract: An electric steering device includes a steering retaining device arranged to retain a steering angle against an external steering force applied from outside of a watercraft to an outboard motor main body. A reverse input shutoff clutch, for example, is preferably used as the steering retaining device. A steering retaining state in which a steering angle of the outboard motor main body is retained can be detected from a steering condition of the outboard motor main body, and a control is made to stop electric power from being supplied to an electric motor steering the outboard motor main body. Accordingly, the steering retaining device retains a steering angle while steering is retained, and thus the electric power supply to the electric motor can be stopped, which allows electric power to be saved. The steering retaining device provides an electric steering device for a watercraft in which no electric power is required when applying a steering retaining force for retaining a counter-steering state.

Abstract: A watercraft includes an operating method in which a present steering wheel rotational angle is detected, and a steering wheel rotational angle variation is calculated by subtracting a steering wheel rotational angle in a preceding control period from the steering wheel rotational angle. Next, a steering angle ratio is set. A target steering angle variation is calculated by multiplying the steering wheel rotational angle variation by the steering angle ratio. Finally, a target steering angle in a present period is calculated by adding the target steering angle variation to a target steering angle in a preceding control period. A steering device is steered based on the target steering angle.

Abstract: An outboard motor is provided on a hull and a steering system is connected electrically to the outboard motor and adapted to steer the hull by rotating the outboard motor. Steering motors are provided to the outboard motor. A control unit has a motor selector for choosing which of the steering motors is used to steer the outboard motor. The control unit stores motor characteristic data about the steering motors and correction data based on factors that change characteristics of the steering motors. The motor selector compares a detection signal of a steering torque detector of a boat with the motor characteristic data and the correction data in order to select at least one of the steering motors to be operated.