A marine propulsion device includes an engine, an exhaust pipe to allow exhaust gas of the engine to pass through the exhaust pipe, and a cooling water supply passage to supply cooling water for the engine into the exhaust pipe toward a downstream side in a flow direction of the exhaust gas and cause the cooling water to flow circumferentially along an inner peripheral surface of the exhaust pipe.

A marine propulsion device includes an engine, an exhaust pipe to allow exhaust gas of the engine to pass through the exhaust pipe, and a cooling water supply passage to supply cooling water for the engine into the exhaust pipe toward a downstream side in a flow direction of the exhaust gas and cause the cooling water to flow circumferentially along an inner peripheral surface of the exhaust pipe.

A marine drive unit for a boat includes a cooling compartment arranged in a drive unit body. The cooling compartment forms part of a closed cooling circuit, where the cooling circuit is arranged to cool propulsion components of the boat, where the cooling compartment comprises an inlet opening, an inlet channel, a lower end, an outlet channel and an outlet opening, where the inlet channel forms a first flow path for a cooling fluid from the inlet opening to the lower end of the cooling compartment. The outlet channel forms a second flow path for the cooling fluid from the lower end of the cooling compartment to the outlet opening, thereby allowing heat from the cooling fluid to dissipate through the outer wall of the drive unit.

There is provided a ship propulsion machine that gives a propulsive force to a ship, including: a power source; a propulsion device that converts power of the power source into a propulsive force of the ship; a power transmission mechanism that transmits power of the power source to the propulsion device; a casing that covers the power source and the power transmission mechanism; and a fine dust capturing device. The fine dust capturing device includes: a water intake which is provided in the casing and through which water around the ship propulsion machine is to be taken in, a capturer that captures fine dust contained in water taken in from the water intake, and a water outlet through which water in which the fine dust was captured by the capturer is to be discharged.

There is provided a ship propulsion machine that gives a propulsive force to a ship, including: a power source; a propulsion device that converts power of the power source into a propulsive force of the ship; a power transmission mechanism that transmits power of the power source to the propulsion device; a casing that covers the power source and the power transmission mechanism; and a fine dust capturing device. The fine dust capturing device includes: a water intake which is provided in the casing and through which water around the ship propulsion machine is to be taken in, a capturer that captures fine dust contained in water taken in from the water intake, and a water outlet through which water in which the fine dust was captured by the capturer is to be discharged.

A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device at a discharge angle relative to a vertical axis. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device along a discharge trajectory parallel to a plane that bisects the device into a port side and a starboard side. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

A marine propulsion device is provided. The device includes an engine, a driveshaft that is caused to rotate by the engine, a cowling system, a gearcase that supports a propulsor for imparting a propulsive force in a body of water, and a cooling water circuit that conveys cooling water that exchanges heat with the engine. The cooling water circuit includes an engine dump hose that extends from a first end to a second end. The first end is coupled to a cooling water outlet of the engine. The cooling water circuit further includes an egress component configured to discharge the cooling water from the device along a discharge trajectory parallel to a plane that bisects the device into a port side and a starboard side. The egress component extends through one or more components of the cowling system and is coupled to the second end of the engine dump hose.

A ship propulsion machine includes a ship propulsion machine main body and a propulsion module. The ship propulsion machine main body includes a power source, a tank storing cooling liquid, a heat sink cooling the cooling liquid, a cooling liquid passage connecting the power source and the heat sink, a pump causing the cooling liquid to flow in the cooling liquid passage, a first housing part housing the heat sink. The propulsion module includes a drive shaft rotated by the power source and a propulsion device converting rotation of the drive shaft into the propulsion force. A connection mechanism separably connecting an output shaft of the power source and the drive shaft is provided on the power source and on the drive shaft. The first housing part and the propulsion device are provided with an attachment mechanism detachably attaching the propulsion module.

A ship propulsion machine includes a ship propulsion machine main body and a propulsion module. The ship propulsion machine main body includes a power source, a tank storing cooling liquid, a heat sink cooling the cooling liquid, a cooling liquid passage connecting the power source and the heat sink, a pump causing the cooling liquid to flow in the cooling liquid passage, a first housing part housing the heat sink. The propulsion module includes a drive shaft rotated by the power source and a propulsion device converting rotation of the drive shaft into the propulsion force. A connection mechanism separably connecting an output shaft of the power source and the drive shaft is provided on the power source and on the drive shaft. The first housing part and the propulsion device are provided with an attachment mechanism detachably attaching the propulsion module.