An axial flux propulsion system for an electric boat that includes interconnecting subsystems including a mounting system, a traction system, a transmission system, an electrical power distribution system, a control system, and a fluid management system, among other boat systems. The traction system typically is an axial flux motor/generator. Various embodiment of the axial flux propulsion system may include a stern drive embodiment and a jet drive embodiment. Portions of the axial flux propulsion system may be both inboard and outboard. A control system may control the operation of the various boat systems including the axial flux motor/generator, and as a result, control the overall operation of the boat.

A marine outboard motor for a marine vessel. The marine outboard motor includes: a housing comprising a chamber and at least one inlet arranged to be submerged, in use, into a body of water in which the marine outboard motor is operated, in order to draw water into the chamber; an engine assembly comprising an internal combustion engine; a drive shaft positioned in the housing, wherein the drive shaft is coupled to the internal combustion engine to drive a propulsion arrangement; a cooling system for cooling the internal combustion engine, the cooling system configured convey drawn water along a coolant flow path through the housing to deliver the drawn water to the internal combustion engine; and a sleeve by which the drive shaft is sealed from drawn water within the housing, the sleeve having first and second ends, wherein at least a part of the drive shaft is encased within the sleeve.

An outboard motor includes a first cooling water passage through which first cooling water including water from outside an outboard motor body passes to cool a first cooling target including at least one of an electrical component other than an engine and fuel in a fuel tank, and a first pump that is an electric pump that pumps the first cooling water from outside of the outboard motor body and flows the first cooling water into the first cooling water passage.

An exhaust gas purification structure of an outboard motor includes an exhaust gas pipe that has an exhaust gas passage through which exhaust gas of an engine can flow; and a catalyst that is provided in the exhaust gas passage and purifies the exhaust gas by allowing the exhaust gas to pass through the inside thereof. The exhaust gas pipe includes a coolant flow passage allowing a coolant that cools the exhaust gas to flow therethrough. An exhaust gas bypass passage allowing the exhaust gas to flow without passing through the catalyst is formed between the catalyst and an inner surface of the exhaust gas pipe forming the exhaust gas passage.

An outboard motor includes an outboard-motor main-body, an anti-ventilation plate, and a foreign-matter collection apparatus. The anti-ventilation plate is provided on the outboard-motor main-body. The foreign-matter collection apparatus is provided above the anti-ventilation plate and outside the outboard-motor main-body and located at a height such that a water intake is submerged under water when a ship to which the outboard-motor main-body has been attached is in a pre-planing state.

An outboard motor includes an upper case, a lower case, a transmission, a clutch, a cooling water passage, a first pump, and a second pump. The transmission is operable to transmit the driving force of the engine. The clutch is connected to the transmission. The cooling water passage is connected to the engine. The cooling water passage is located in the upper case and the lower case. The first pump is connected to the transmission via the clutch. The first pump is driven by the driving force of the engine to send cooling water to the engine through the cooling water passage. The second pump is connected to the transmission. The second pump is driven by the driving force of the engine to send the cooling water to the engine through the cooling water passage.

A marine cooling system performs a temperature adjustment of an object to be cooled such as an internal combustion engine of a marine vessel. The marine cooling system includes a water supply flow passage to supply cooling water to the object, a water drain flow passage to drain the cooling water from the object to reduce an amount of the cooling water that contacts the object, and a flow passage controller to shut off the water to the drain flow passage.

An exhaust gas purification structure of an outboard motor includes an exhaust gas pipe that has an exhaust gas passage through which exhaust gas of an engine can flow; and a catalyst that is provided in the exhaust gas passage and purifies the exhaust gas by allowing the exhaust gas to pass through the inside thereof. The exhaust gas pipe includes a coolant flow passage allowing a coolant that cools the exhaust gas to flow therethrough. An exhaust gas bypass passage allowing the exhaust gas to flow without passing through the catalyst is formed between the catalyst and an inner surface of the exhaust gas pipe forming the exhaust gas passage.

A cooling device for a power source for a boat propulsion apparatus includes a cooling water passage. The cooling water passage includes a passage provided in the power source, in which an engine or an electric motor is used as the power source of the boat propulsion apparatus that propels a boat. Water from outside the boat is taken into the cooling water passage as cooling water to cool the power source, and the cooling water after cooling the power source is drained from the cooling water passage. From the cooling water flowing through the cooling water passage, foreign substances having a size that clogs the cooling water passage are removed. The cooling water passage is provided with a filter device which can filter residual foreign substances remaining in the cooling water.

An improved outboard and steering control system that includes a removable lower drive unit with the ability to rotate 360 degrees or more. The embodiments shown herein are also design for electric outboard marine motors with cooling systems connected between the lower drive unit and the upper housing unit. This system allows the ability to configure an upper drive unit with multiple different variations of a lower drive unit and improve the ability to maneuver vessels with the increased 360-degree directional range.