Abstract: An outboard motor steering system includes a hydraulic fluid supply mechanism connected to the steering hydraulic cylinder to supply hydraulic fluid thereto disposed in a space formed between the stern brackets and the swivel case. In other words, since the hydraulic fluid supply mechanism is incorporated into the outboard motor as a unit, the structure can be made simpler than that of the related art and the number of parts in the entire system can be reduced and moreover the work of installation into the boat's hull can be simplified. Also, operating efficiency is improved for an electric motor serving as the source of driving force for a hydraulic pump that supplies hydraulic fluid to the hydraulic cylinder used for steering, and power consumption is reduced.

Abstract: An outboard motor includes an elastic seal lid attached to an under cover to form a hermetic seal between the under cover and an exhaust release pipe while closing an opening of the under cover from which an outlet portion of the exhaust release pipe projects outwardly. The seal lid includes a tubular seal portion projecting from at least one surface of a plate-like body of the seal lid. The tubular seal portion has annular seal lips fitted around an outer circumferential surface of the exhaust release pipe. The tubular seal portion is elastically deformable relative to the lid body to thereby take up or absorb an offset between the exhaust release pipe and the opening of the under cover produced due to cumulative manufacturing and assembling tolerances of relevant parts of the outboard motor.

Abstract: An outboard motor having a grommet mounted on a lower cover is disclosed. The grommet is positioned outward from an area directly under a surface in which an upper cover and lower cover meet as viewed from above. A presser cover for pressing the upper half of the grommet expands in the lateral direction and has on the lower end portion a first concavity that opens in the downward direction and conforms to the external shape of the grommet.

Abstract: In an outboard engine unit, a cover assembly, defining a lower half section of an engine room, is composed of left and right cover members each formed of resin, and a bracket is fixed to a rear portion of the engine or engine support structure. The left and right cover members are fixed at their respective rear portions to the bracket. Centerline of an engine cylinder is offset from a centerline of the engine room toward one of left and right sides of the unit, and an ignition plug is provided on the other side opposite from the one side toward which the engine cylinder centerline is offset.

Abstract: A seal member seals a gap between upper and lower cover members of an engine cover of an outboard motor. The seal member includes a supporting portion and a sealing portion integral with the supporting portion. The supporting portion has such a high spring modulus that the supporting portion is not plastically deformed with a load is applied to the supporting portion when the upper cover member is locked to the lower cover member. The sealing portion is hollow and has such a small spring modulus that the sealing portion can readily flex into close contact with the upper and lower cover members so as to provide an improved seal between the upper and lower cover members.

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: An outboard motor steering control system operates at starting of the engine to compare the output of the steering wheel angle sensor which indicates the turned angle of the steering wheel and the output of the rotation angle sensor which indicates the rotation angle of the swivel shaft, determines whether there is a phase difference in steering angle therebetween, responds to any phase difference found by, at the time the boat operator turns the steering wheel, controlling the operation of the actuator connected to the swivel shaft so as to eliminate the difference, and further operates to inform the boat operator of the difference. Owing to this configuration, the difference can be eliminated without causing the boat operator to experience an unnatural feel.

Abstract: A forward/backward gear shifting mechanism for an outboard engine includes an operating cable passed through an outer pipe fixed to a bracket attached to an under cover and extended into an engine room, a shift rod for shifting a forward/backward gear, a driving arm for turning the shift rod, and a transmission mechanism linked to the operating cable to transmit operating force to the driving arm. The transmission mechanism includes an arm mechanism including an input arm, an output arm and a pivotal shaft and supported for turning about a fixed rotational axis by support members on the engine unit. The operating cable is linked to the input arm of the transmission mechanism by a slider, i.e., a linking member. A first connecting member connecting the input member and the slider is nearer to the bracket than a second connecting member connecting the operating cable and the slider.

Abstract: An outboard motor includes an elastic seal lid attached to an under cover to form a hermetic seal between the under cover and an exhaust release pipe while closing an opening of the under cover from which an outlet portion of the exhaust release pip projects outwardly. The seal lid includes a tubular seal portion projecting from at leaser one surface of a plate-like body of the seal lid. The tubular seal portion has annular seal lips fitted around an outer circumferential surface of the exhaust release pipe. The tubular seal portion is elastically deformable relative to the lid body to thereby take up or absorb an offset between the exhaust release pipe and the opening of the under cover produced due to cumulative manufacturing and assembling tolerances of relevant parts of the outboard motor.

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: An outboard motor having an intake passage unit for introducing air into an engine compartment is provided. The intake passage unit has two intake passage portions disposed at the left and the right of an engine, extending vertically, to reduce the fore-and-aft length of an engine cover. The left and right intake passage portions communicate at their upper portions with air introduction openings formed in the engine cover.

Abstract: An outboard engine has an internal combustion engine as a prime mover, a throttle valve device including a valve element and a valve shaft supporting the valve element, and combined with the internal combustion engine, a driven unit combined with the throttle valve device, and a drive unit for driving the driven unit. The drive unit is capable of smoothly transmitting an external throttle-operating force to the driven unit regardless of its position. A throttle valve operating mechanism connects an operating lever included in the driven unit, and a throttle-operating Bowden cable included in the drive unit. The throttle valve operating mechanism is a linkage including plural links. Joints joining the adjacent joining parts of those links are ball-and-socket joints, respectively. The valve shaft has one end connected to the operating lever and the other end connected to a throttle position sensor. The valve shaft is inclined to a horizontal plane.

Abstract: An outboard motor steering system includes a hydraulic fluid supply mechanism connected to the steering hydraulic cylinder to supply hydraulic fluid thereto disposed in a space formed between the stern brackets and the swivel case. In other words, since the hydraulic fluid supply mechanism is incorporated into the outboard motor as a unit, the structure can be made simpler than that of the related art and the number of parts in the entire system can be reduced and moreover the work of installation into the boat's hull can be simplified. Also, operating efficiency is improved for an electric motor serving as the source of driving force for a hydraulic pump that supplies hydraulic fluid to the hydraulic cylinder used for steering, and power consumption is reduced.

Abstract: An outboard motor includes an elastic seal lid attached to an under cover to form a hermetic seal between the under cover and an exhaust release pipe while closing an opening of the under cover from which an outlet portion of the exhaust release pipe projects outwardly. The seal lid includes a tubular seal portion projecting from at least one surface of a plate-like body of the seal lid. The tubular seal portion has annular seal lips fitted around an outer circumferential surface of the exhaust release pipe. The tubular seal portion is elastically deformable relative to the lid body to thereby take up or absorb an offset between the exhaust release pipe and the opening of the under cover produced due to cumulative manufacturing and assembling tolerances of relevant parts of the outboard motor.

Abstract: An outboard motor includes an under cover covering a part of an engine, a mount case supporting the engine, and an oil pan provided below the mount case. The under cover has an opening formed at a place opposite to a drain unit provided at a lower portion of the oil pan. The opening can be opened and closed by a drain cover having first and second locks. A release of the first lock is operated to allow the drain cover to be attached and detached to and from the opening with a single motion.

Abstract: An outboard motor has an engine and a cover structure comprised of first and second cover members detachably connected to one another to define at least part of an engine compartment accommodating therein at least a portion of the engine. A cover body is mounted on the cover structure and has a tubular portion with an open end through which cables are introduced into the engine compartment. A sealing member extends into the tubular portion of the cover body through the open end for retaining in a sealed state the cables introduced into the engine compartment. The sealing member has an outer peripheral surface and elastically deformable lip portions extending from the outer peripheral surface and contacting an inner peripheral surface of the tubular portion in the region of the open to form a hermetic seal between the lip portions and the inner peripheral surface of the tubular portion.

Abstract: An outboard motor has an under cover forming a lower part of an engine room in which an engine is installed. The under cover has a pair of right and left cover members detachably connected together along opposing vertical edges thereof; an opening formed in at least one of the cover members for allowing access to the engine. The opening is vertically spaced from an upper edge of the under cover and extends contiguously from the vertical edge of the at least one cover member. A lid made of elastic material is attached to an outer surface of the under cover so as to close the opening of the under cover, the lid being elastically deformable to open and close the opening.

Abstract: An outboard motor has an engine, a propeller drivable by the engine, and a drive shaft for transmitting a driving force from the engine to the propeller. A casing assembly supports the engine and rotatably supports and accommodates the drive shaft. A cover structure defines at least part of an engine space accommodating therein the engine. The cover structure has a resin cover body comprised of at least first and second cover members detachably connected to one another, and a frame assembly integrally connected to an inner surface of the first cover member for reinforcement threof. The first cover member has an opened flange receiving a seal of the second cover member. The frame assembly extends along a contour of the opened flange.

Abstract: Fixedly joining sections are provided on opposed joining edges of left and right undercover members defining part of an engine space of an outboard engine unit. The opposed joining edges are abutted against each other with the joining sections of the left and right undercover members overlapped in face-to-face relation with each other in a front-and-rear direction of the outboard engine unit. Fasteners, such as bolts, fasten together the overlapped joining sections in the front-and-rear direction, to thereby join together the left and right undercover members. The joining sections may be provided on frame members integrally secured to the respective inner side surfaces of resin-made outer wall sections of the left and right undercover members.