An exhaust device discharging exhaust gas from an engine of a ship propulsion machine includes an exhaust passage through which the exhaust gas flows and a catalyst device purifying the exhaust gas. The exhaust passage includes a first exhaust pipe and a second exhaust pipe connected to an outflow side of the first exhaust pipe. The catalyst device includes a metal catalyst including a metal catalyst carrier, an outer shell portion having a tubular shape and accommodating the metal catalyst, and a holding portion provided in the outer shell portion, having a brim shape protruding radially outward beyond an outer circumferential surface of the outer shell portion, and holding the catalyst device. The catalyst device is held in the exhaust passage by the holding portion being sandwiched between an outflow-side end portion of the first exhaust pipe and an inflow-side end portion of the second exhaust pipe.

An exhaust device discharging exhaust gas from an engine of a ship propulsion machine includes an exhaust passage through which the exhaust gas flows and a catalyst device purifying the exhaust gas. The exhaust passage includes a first exhaust pipe and a second exhaust pipe connected to an outflow side of the first exhaust pipe. The catalyst device includes a metal catalyst including a metal catalyst carrier, an outer shell portion having a tubular shape and accommodating the metal catalyst, and a holding portion provided in the outer shell portion, having a brim shape protruding radially outward beyond an outer circumferential surface of the outer shell portion, and holding the catalyst device. The catalyst device is held in the exhaust passage by the holding portion being sandwiched between an outflow-side end portion of the first exhaust pipe and an inflow-side end portion of the second exhaust pipe.

An outboard motor is provided with: an engine cover in which a first outside air inlet port, an exhaust port, and second outside air inlet ports are formed; and a lower housing that is disposed below the engine cover. The engine cover is provided with a front guide and a rear guide that guide outside air, introduced respectively from the first outside air inlet port and the second outside air inlet ports into the engine cover, downward in the gravity direction.

An outboard motor has a powerhead that causes rotation of a driveshaft, a steering housing located below the powerhead, wherein the driveshaft extends from the powerhead into the steering housing; and a lower gearcase located below the steering housing and supporting a propeller shaft that is coupled to the driveshaft so that rotation of the driveshaft causes rotation of the propeller shaft. The lower gearcase is steerable about a steering axis with respect to the steering housing and powerhead.

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 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.

A vessel propulsion apparatus includes an engine and a propulsion unit to be driven by the engine. The engine includes cylinders arranged in series, exhaust ports respectively connected to combustion chambers of the cylinders and curved in a predetermined downstream direction to allow exhaust gases to flow out from the combustion chambers, and a collecting exhaust pipe. The collecting exhaust pipe is integral with the exhaust ports, and extends in the downstream direction to allow exhaust gases in the exhaust ports to flow in the downstream direction. At least one of a plurality of connector portions that individually connect the exhaust ports to the collecting exhaust pipe includes a concave portion at an inner surface thereof.

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.