Abstract: Even in the case where a crankshaft extends in a substantially vertical direction, it is possible to reduce a situation that sprays of fuel injected from injectors may adhere to inner wall surfaces of intake passages, and it is possible to make the fuel supply to combustion chambers stable.

Abstract: An outboard motor has a vertical-shaft vee engine unit provided with a crankshaft arranged approximately vertically and left and right cylinder units aligned to be open backward in a “V” shape as seen in a plan view. A surge tank and an air intake system unit provided with an intake pipe to connect the surge tank to intake ports of the left and right cylinder heads are arranged in a center of a width direction of a rear side of the engine unit. In addition, an electronic control unit is arranged in an approximate center of a height direction in the right side of the air intake system unit. Furthermore, a high-pressure fuel filter is arranged in an approximate center of a height direction in the left side of the air intake system unit. Moreover, a vapor separator embedded with a high-pressure fuel pump is arranged under the high-pressure fuel filter.

Abstract: An outboard motor equipped with a four-stroke engine and provided with a catalyst installation structure, in which an exhaust passage is connected to the exhaust ports of the plurality of the cylinders to lead the exhaust gas out of the engine is provided with a catalyst storage chamber configured to store a catalytic converter for cleaning up the exhaust gas, the exhaust passage being integrally formed to the cylinder block, and the catalytic converter is mounted to the catalyst storage chamber by being inserted from a lower side thereof in such a manner as that at least one side end portion thereof is fitted to the catalyst storage chamber to permit expansion of the catalytic converter in an axial direction thereof.

Abstract: Even in the case where a crankshaft extends in a substantially vertical direction, it is possible to reduce a situation that sprays of fuel injected from injectors may adhere to inner wall surfaces of intake passages, and it is possible to make the fuel supply to combustion chambers stable.

Abstract: An outboard motor includes a drive shaft that transmits rotational power from an engine, a shift unit provided in the middle of the drive shaft, and a water pump that feeds a coolant to the engine. The drive shaft has a first input shaft that receives rotational power transmitted from the engine and a second input shaft that receives rotational power transmitted from the first input shaft. The shift unit has an upper gear rotating in synchronization with the first input shaft, an intermediate gear meshing with the upper gear at all times, and an intermediate shaft extending to the rear side from the intermediate gear and rotating in synchronization. The oil pump as an accessory is operated by the rotational power transmitted to the intermediate shaft.

Abstract: An outboard motor includes a drive shaft that transmits rotational power from the engine, and a shift unit provided in the middle of the drive shaft. The shift unit has a dog clutch that reciprocates in parallel with the drive shaft, a shift fork member that reciprocates the dog clutch in parallel with the drive shaft, and a linear motion type actuator that reciprocates the shift fork member in parallel with the drive shaft. The actuator is arranged in the vicinity of the front side of the dog clutch such that the direction of the rectilinear motion of the screw shaft is in parallel with the axial line of the drive shaft, and the shift fork member is connected to the screw shaft.

Abstract: An outboard motor includes a cooling water passage structure, in which a combustion chamber periphery water jacket through which the cooling water flows around the combustion chamber and an exhaust port periphery water jacket through which the cooling water flows around the exhaust port are formed in the cylinder head, a cylinder periphery water jacket through which the cooling water flows around the cylinder is formed in the cylinder block, and an exhaust passage periphery water jacket through which the cooling water flows around the exhaust passage is formed around the exhaust passage. The water jackets are connected such that the cooling water from the water passage will flow through the combustion chamber periphery water jacket, the exhaust port periphery water jacket, the cylinder periphery water jacket, and the exhaust passage periphery water jacket in order.

Abstract: In an outboard motor equipped with a V-type four-cycle engine provided with a left bank extending leftward and obliquely rearward and a right bank extending rightward and obliquely rearward, a drive shaft is perpendicularly disposed in the outboard motor body so as to transmit a driving force from the engine to a propeller disposed below the engine, and center positions of the left side exhaust passage and the right side exhaust passage are positioned forward than the drive shaft in a front-and-rear direction in an advancing direction of the outboard motor.

Abstract: In an exhaust passage structure in a V-type four-stroke engine of an outboard motor, an exhaust passage is connected to the respective exhaust ports of a plurality of cylinders so that-a first exhaust passage portion is provided on at least one lateral side of the cylinder block in a width direction and collects exhaust gas discharged from the respective exhaust ports of the plurality of cylinder assemblies, while a second exhaust passage portion connects the first exhaust passage portion with an exhaust muffler chamber installed outside the engine, and an exhaust guiding portion is provided so as to oppose to a joint surface between the cylinder block and the cylinder head in a manner to be located in the first exhaust passage portion to guide the exhaust gas discharged from the exhaust ports to a connecting portion between the first exhaust passage portion and the second exhaust passage portion.

Abstract: An outboard motor equipped with a four-stroke engine and provided with a catalyst installation structure, in which an exhaust passage is connected to the exhaust ports of the plurality of the cylinders to lead the exhaust gas out of the engine is provided with a catalyst storage chamber configured to store a catalytic converter for cleaning up the exhaust gas, the exhaust passage being integrally formed to the cylinder block, and the catalytic converter is mounted to the catalyst storage chamber by being inserted from a lower side thereof in such a manner as that at least one side end portion thereof is fitted to the catalyst storage chamber to permit expansion of the catalytic converter in an axial direction thereof.

Abstract: Disclosed is an outboard motor including a drive shaft that transmits rotational power from an engine, a shift unit provided in the middle of the drive shaft, and a water pump that feeds a coolant to the engine. The drive shaft has a first input shaft that receives the rotational power transmitted from the engine and a second input shaft that receives the rotational power transmitted from the first input shaft. The shift unit and the water pump are integrated into a single shift unit module installed detachably to the lower unit casing.

Abstract: An outboard motor has a vertical-shaft vee engine unit provided with a crankshaft arranged approximately vertically and left and right cylinder units aligned to be open backward in a “V” shape as seen in a plan view. A surge tank and an air intake system unit provided with an intake pipe to connect the surge tank to intake ports of the left and right cylinder heads are arranged in a center of a width direction of a rear side of the engine unit. In addition, an electronic control unit is arranged in an approximate center of a height direction in the right side of the air intake system unit. Furthermore, a high-pressure fuel filter is arranged in an approximate center of a height direction in the left side of the air intake system unit. Moreover, a vapor separator embedded with a high-pressure fuel pump is arranged under the high-pressure fuel filter.

Abstract: An outboard motor includes a drive shaft that transmits rotational power from an engine, a shift unit provided in the middle of the drive shaft, and a water pump that feeds a coolant to the engine. The drive shaft has a first input shaft that receives rotational power transmitted from the engine and a second input shaft that receives rotational power transmitted from the first input shaft. The shift unit has an upper gear rotating in synchronization with the first input shaft, an intermediate gear meshing with the upper gear at all times, and an intermediate shaft extending to the rear side from the intermediate gear and rotating in synchronization. The oil pump as an accessory is operated by the rotational power transmitted to the intermediate shaft.

Abstract: An exhaust apparatus of an outboard motor equipped with a four-stroke engine includes an exhaust pipe having a cylindrical shape and being connected to an exhaust passage of an engine holder, wherein the exhaust pipe is disposed in an exhaust passage of the exhaust manifold in a manner being erected upright in parallel to the crankshaft, and the exhaust pipe has an upper end opened in an upper portion of the exhaust passage and a lower end supporting the cylinder block, and the exhaust manifold and the exhaust pipe are provided with a gap therebetween in a plan view acting as an exhaust collection space adapted to collect exhaust gas from the exhaust manifold.

Abstract: A forward/backward switching mechanism having an intermediate gear supported by an intermediate shaft perpendicular to a drive shaft is interposed between first and second input shafts. A clutch body is a dog clutch having upper and lower locking dogs. As the dog clutch moves along an axial direction of the second input shaft and is engaged with upper or lower gears, rotation of the first input shaft is forwardly or reversely transmitted to the second input shaft.

Abstract: The outboard motor includes a lower unit that rotatably supports a propeller shaft and a shift unit that switches a shift position. A drive shaft that transmits rotational power to the propeller shaft has upper and lower drive shafts provided coaxially and in series side by side. The shift unit has an upper gear rotating in synchronization with the upper drive shaft, a lower gear provided rotatably with respect to the lower drive shaft, an intermediate gear that transmits rotation of the upper gear to the lower gear, and a bearing that rotatably supports the middle shaft provided with the intermediate gear. The intermediate gear and the bearing are modularized and are detachably installed to the lower unit.

Abstract: The outboard motor includes a lower unit that rotatably supports a propeller shaft installed with propellers, and a shift unit that switches a shift position. The lower unit is provided with an upwardly opened shift unit storage chamber and a lid member that covers the upper side of the shift unit storage chamber. The shift unit has a dog clutch that switches the shift position by reciprocating in parallel with the drive shaft, a shift fork member that reciprocates the dog clutch in parallel with the drive shaft, and an actuator that reciprocates the shift fork member in parallel with the drive shaft. The actuator is supported by the lid member.

Abstract: An outboard motor includes a drive shaft that transmits rotational power from the engine, and a shift unit provided in the middle of the drive shaft. The shift unit has a dog clutch that reciprocates in parallel with the drive shaft, a shift fork member that reciprocates the dog clutch in parallel with the drive shaft, and a linear motion type actuator that reciprocates the shift fork member in parallel with the drive shaft. The actuator is arranged in the vicinity of the front side of the dog clutch such that the direction of the rectilinear motion of the screw shaft is in parallel with the axial line of the drive shaft, and the shift fork member is connected to the screw shaft.

Abstract: A transmission is structured to include a drive shaft, a counter shaft disposed in parallel with the drive shaft, a gear train bridged between each of a drive shaft input shaft and output shaft and the counter shaft, and a dog clutch mechanism selectively switching a high shift speed and a low shift speed in a transmission chamber. The transmission includes a drive device driving the dog clutch mechanism constituted of a hydraulic drive device driven by a hydraulic cylinder, the hydraulic cylinder being disposed in the transmission chamber.

Abstract: A water jacket is attached to an exhaust manifold connected to an exhaust port to annularly cover an outer side of an exhaust channel in the exhaust manifold. An engine cooling coolant is made to flow as a cooling medium of the water jacket of the exhaust manifold. An exhaust pipe in a siphon shape is connected to the exhaust manifold, a water jacket is attached so as to annularly cover an outer side of a front half portion of the siphon shape, and seawater is directly supplied into the water jacket to flow therein. Consequently, an exhaust device of an outboard motor practically having a compact structure and excellent exhaust performance and accordingly realizing excellent engine performance is provided.