The outboard motor includes a drive shaft 4 that extends in a vertical direction, a propeller shaft that is connected to the drive shaft 4 to intersect the drive shaft 4, an upper case 2 that accommodates the drive source, a lower case 8 that accommodates the propeller shaft, and a height adjusting unit 9 that adjusts a height position between the upper case 2 and the lower case 8. The height adjusting unit 9 includes a first member 41 that is disposed coaxially with an axis C of the drive shaft 4, a second member 42 that is fixed to the lower case 8 and is screwed to the first screw portion 48, a rotation device 43 that rotates the first member 41, and a regulating portion 44 that restricts relative rotation between the first member 41 and the second member 42.

The outboard motor includes a drive shaft 4 that extends in a vertical direction, a propeller shaft that is connected to the drive shaft 4 to intersect the drive shaft 4, an upper case 2 that accommodates the drive source, a lower case 8 that accommodates the propeller shaft, and a height adjusting unit 9 that adjusts a height position between the upper case 2 and the lower case 8. The height adjusting unit 9 includes a first member 41 that is disposed coaxially with an axis C of the drive shaft 4, a second member 42 that is fixed to the lower case 8 and is screwed to the first screw portion 48, a rotation device 43 that rotates the first member 41, and a regulating portion 44 that restricts relative rotation between the first member 41 and the second member 42.

A marine propulsion device includes a first gear, a second gear, a third gear, a case, a partition wall, and a first flow path. The case includes an internal space in which the first gear, the second gear, and the third gear are located. The partition wall is located between the second gear and the third gear in the internal space. The partition wall partitions the internal space into a first space and a second space. The second gear is located in the first space. The third gear is located in the second space. The first flow path communicates the first space with the second space. The first flow path is located on a same side as the first gear with respect to a center line of the second gear and the third gear.

A marine propulsion device includes a first gear, a second gear, a third gear, a case, a partition wall, and a first flow path. The case includes an internal space in which the first gear, the second gear, and the third gear are located. The partition wall is located between the second gear and the third gear in the internal space. The partition wall partitions the internal space into a first space and a second space. The second gear is located in the first space. The third gear is located in the second space. The first flow path communicates the first space with the second space. The first flow path is located on a same side as the first gear with respect to a center line of the second gear and the third gear.

A marine power supply system includes a battery unit including a first battery to supply power to a starter that starts an engine, and a second battery to supply power to an electric motor, and a power distributor connected to the first battery and the second battery. The power distributor outputs a demand power amount of power required by the first battery to the first battery, and outputs at least a portion of surplus power to the second battery when a total demand power amount required by the battery unit includes the surplus power.

A marine power supply system includes a battery unit including a first battery to supply power to a starter that starts an engine, and a second battery to supply power to an electric motor, and a power distributor connected to the first battery and the second battery. The power distributor outputs a demand power amount of power required by the first battery to the first battery, and outputs at least a portion of surplus power to the second battery when a total demand power amount required by the battery unit includes the surplus power.

A power transmission device for an outboard motor, comprising a drive shaft, an endless loop flexible drive coupling and a propeller shaft, wherein the endless loop flexible drive coupling operatively connects said drive shaft to said propeller shaft for transferring output power from the drive shaft to the propeller shaft. The power transmission device comprises a first drive shaft, a second drive shaft, a first endless loop flexible drive coupling, a second endless loop flexible drive coupling, a first propeller shaft and a second propeller shaft, wherein the first propeller shaft is connected to the first drive shaft through the first endless loop flexible drive coupling to rotate the first propeller shaft in a first direction, and wherein the second propeller shaft is connected to the second drive shaft through the second endless loop flexible drive coupling to rotate the second propeller shaft in a second direction opposite to the first direction.

A multi-plate clutch transmission includes an arrangement for selectively engaging the clutch by moving the sleeve to cause one or more friction disks on a sleeve connected to a shaft to move into contact with one or more friction disks on a clutch basket connected to a gear driven by another gear and another shaft driven by a prime mover. An arrangement for selectively disengaging the clutch is provided that uses prime mover torque to move the one or more friction disks on the sleeve out of contact with the one or more.friction disks on the clutch basket.

A multi-plate clutch transmission includes an arrangement for selectively engaging the clutch by moving the sleeve to cause one or more friction disks on a sleeve connected to a shaft to move into contact with one or more friction disks on a clutch basket connected to a gear driven by another gear and another shaft driven by a prime mover. An arrangement for selectively disengaging the clutch is provided that uses prime mover torque to move the one or more friction disks on the sleeve out of contact with the one or more.friction disks on the clutch basket.

An outboard motor includes an engine, a generator to generate power by driving of the engine, a driving force transmitter to transmit a driving force from the engine, a propeller shaft to rotate by being switched from a neutral state in which a clutch is disconnected from the driving force transmitter of the engine at idle to a non-neutral state in which the clutch is connected to the driving force transmitter, and a controller configured or programmed to perform a control to reduce a rotation speed of the engine by regeneration of the generator based on a user's switching operation on a shift operator to switch the outboard motor from the neutral state to the non-neutral state, and then connect the clutch to the driving force transmitter while rotating the engine.