An outboard motor includes a drive shaft cover to cover a drive shaft extending downwardly from an engine, a lower unit turnable with respect to the drive shaft cover, and a harness. A lower housing of the lower unit houses a lower portion of the drive shaft and an electrical component. The harness is connected to the electrical component through an upper space provided in the drive shaft cover and through a lower space that communicates with the upper space from below in the lower housing.

An underwater propulsion unit is provided for an outboard motor or a pod drive. The underwater propulsion unit includes a plastic housing designed for water to flow around, and a metal housing in which an electrical drive is received. The electrical drive is received in the metal housing so as to be sealed off from the surroundings in a watertight manner, and the metal housing is arranged inside the plastic housing.

An outboard motor includes a power source, a drive shaft, a propeller shaft, a propeller attached to the propeller shaft, a case covering the power source, the drive shaft, and the propeller shaft, a water intake passage provided in the case, through which water is taken into the case from an outside of the outboard motor, a first pump configured to be driven by rotation of the drive shaft and to supply the water taken in from the water intake passage to the power source as cooling water, and a second pump configured to be driven by rotation of the drive shaft and to supply the water taken in from the water intake passage to the power source as the cooling water. The first pump and the second pump are arranged in a distributed manner in the outboard motor.

An outboard motor includes a power source, a drive shaft, a propeller shaft, a propeller attached to the propeller shaft, a case covering the power source, the drive shaft, and the propeller shaft, a water intake passage provided in the case, through which water is taken into the case from an outside of the outboard motor, a first pump configured to be driven by rotation of the drive shaft and to supply the water taken in from the water intake passage to the power source as cooling water, and a second pump configured to be driven by rotation of the drive shaft and to supply the water taken in from the water intake passage to the power source as the cooling water. The first pump and the second pump are arranged in a distributed manner in the outboard motor.

A cooling structure for an outboard motor comprises an oil case which has an oil chamber for storing lubricant oil for an engine. Said cooling structure further comprises: a main exhaust gas passage which guides exhaust gas to a lower side; a cooling water outbound path which guides cooling supply water taken from outside the outboard motor to an upper side, and cools the periphery of the main exhaust gas passage in the oil case by means of the cooling supply water; a cooling water inbound path which guides cooling discharge water that has cooled the engine to the lower side and cools the oil chamber by means of said cooling discharge water; and a mixed fluid passage which, on a side below the oil case, cools the exhaust gas by mixing the exhaust gas and the cooling discharge water.

A cooling structure for an outboard motor comprises an oil case which has an oil chamber for storing lubricant oil for an engine. Said cooling structure further comprises: a main exhaust gas passage which guides exhaust gas to a lower side; a cooling water outbound path which guides cooling supply water taken from outside the outboard motor to an upper side, and cools the periphery of the main exhaust gas passage in the oil case by means of the cooling supply water; a cooling water inbound path which guides cooling discharge water that has cooled the engine to the lower side and cools the oil chamber by means of said cooling discharge water; and a mixed fluid passage which, on a side below the oil case, cools the exhaust gas by mixing the exhaust gas and the cooling discharge water.

An outboard-motor vibration-isolating cooler system apparatus providing a retrofit substitute for the midsection and the lower unit of a standard outboard motor, having a substitute closed-loop cooling system with an exterior heat exchanger, a substitute oil reservoir, a substitute exhaust system, and a substitute propulsion system with an isolating power-take-off shaft, allowing an existing standard outboard-motor powerhead to be used in conditions not conducive to standard open-loop water cooling, such as shallow-water, muddy-water, obstructed-water, seawater, or corrosive-water conditions.

An outboard-motor vibration-isolating cooler system apparatus providing a retrofit substitute for the midsection and the lower unit of a standard outboard motor, having a substitute closed-loop cooling system with an exterior heat exchanger, a substitute oil reservoir, a substitute exhaust system, and a substitute propulsion system with an isolating power-take-off shaft, allowing an existing standard outboard-motor powerhead to be used in conditions not conducive to standard open-loop water cooling, such as shallow-water, muddy-water, obstructed-water, seawater, or corrosive-water conditions.

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.

An outboard motor having an internal combustion engine that causes rotation of a driveshaft, a planetary transmission that operatively connects the driveshaft to a transmission output shaft, a band brake configured to shift the planetary transmission amongst a forward gear, neutral gear and reverse gear, a hydraulic actuator is configured to actuate the band brake, and a cooling water circuit that extends adjacent to the hydraulic actuator so that the hydraulic actuator exchanges heat with cooling water in the cooling water circuit.