An outboard motor includes an oil cooler, an engine cooling water passage, an oil cooling water passage, and a water discharge passage. The oil cooler is disposed forward of a crankshaft. The engine cooling water passage is disposed inside an engine. The oil cooling water passage is connected to the oil cooler and branches from the engine cooling water passage. The water discharge passage is connected to the oil cooler. The water discharge passage is disposed lower than the oil cooler and forward of a center axis of the crankshaft.

A heat exchange system for use on an engine-powered watercraft includes a liquid cooling system for cooling the engine using a first heat exchanger and a water heating system using a second heat exchanger for heating water. Raw water from an external water source is passed through each heat exchanger. Water used to cool the engine coolant inside the first heat exchanger exits the watercraft. Water heated by the second heat exchanger is passed to either an intake conduit or at least one onboard accessory system for flushing thereof to kill aquatic invasive species. A valve inside the second heat exchanger opens to release heated water when the heated water reaches a temperature of at least 140 F. Heated coolant from the first heat exchanger passes through the second heat exchanger to transfer heat to the water inside the second heat exchanger.

A V-type engine in which exhaust pipe arrangement is easily performed and purification of exhaust gas can be performed by a single catalyst. Cylinders where pistons operate are arranged in a V-shape, a crankshaft driven by the driving of the pistons is disposed vertically, exhaust pipes communicating with exhaust openings in the respective banks of a cylinder head are included, rear exhaust pipes in the respective banks are merged outside on a side of the crankshaft, and a catalyst holder that holds a catalyst is provided in a merge portion of the rear exhaust pipes. Since the rear exhaust pipes in the respective banks are merged and the catalyst holder is provided in this merge portion, exhaust gas from each bank can be purified by the single catalyst, so that the number of catalysts installed is reduced to thus be able to reduce manufacturing cost.

A heat exchange system for use on an engine-powered watercraft includes a liquid cooling system for cooling the engine using a first heat exchanger and a water heating system using a second heat exchanger for heating water. Raw water from an external water source is passed through each heat exchanger. Water used to cool the engine coolant inside the first heat exchanger exits the watercraft. Water heated by the second heat exchanger is passed to either an intake conduit or at least one onboard accessory system for flushing thereof to kill aquatic invasive species. A valve inside the second heat exchanger opens to release heated water when the heated water reaches a temperature of at least 140 F. Heated coolant from the first heat exchanger passes through the second heat exchanger to transfer heat to the water inside the second heat exchanger.

A marine propulsion device includes an internal combustion engine; an axially elongated exhaust conduit that conveys exhaust gas from the upstream internal combustion engine to a downstream outlet; a cooling water sprayer that is configured to spray a flow of cooling water radially outwardly toward an inner diameter of the axially elongated exhaust conduit; a temperature sensor located downstream of the cooling water sprayer and configured to sense temperature of the exhaust gas and cooling water; and a controller configured to identify a fault condition associated with the cooling water sprayer based on the temperature of the exhaust gas and cooling water.

An outboard motor includes a water jacket provided in a water-cooled engine, a first channel configured to allow a downstream-side end of a coolant flow of the water jacket to communicate with the external air, a thermo-valve provided between a downstream-side end of the coolant flow of the water jacket and an upstream-side end of the coolant flow of the first channel, a second channel configured to allow an upstream side of the coolant flow of the thermo-valve to communicate with the external air, and a second valve configured to open or close a second channel.

An outboard motor includes an oil cooler, an engine cooling water passage, an oil cooling water passage, and a water discharge passage. The oil cooler is disposed forward of a crankshaft. The engine cooling water passage is disposed inside an engine. The oil cooling water passage is connected to the oil cooler and branches from the engine cooling water passage. The water discharge passage is connected to the oil cooler. The water discharge passage is disposed lower than the oil cooler and forward of a center axis of the crankshaft.

An outboard motor includes a water jacket provided in a water-cooled engine, a first channel configured to allow a downstream-side end of a coolant flow of the water jacket to communicate with the external air, a thermo-valve provided between a downstream-side end of the coolant flow of the water jacket and an upstream-side end of the coolant flow of the first channel, a second channel configured to allow an upstream side of the coolant flow of the thermo-valve to communicate with the external air, and a second valve configured to open or close a second channel.

A system for flushing a cooling water pathway in a marine propulsion device includes a water control device, an electric power control device, a data communication module, and a controller. The controller controls the water control device to supply the water from a water source to the cooling water pathway to flush the cooling water pathway. The controller controls the electric power control device to supply electric power to the marine propulsion device during the flushing. The controller determines whether to end the flushing or not. When it is determined to end the flushing, the controller controls the electric power control device to stop the supply of electric power to the marine propulsion device, and controls the data communication module to notify the end of the flushing to a terminal of a user of the marine propulsion device.

Described herein is a method and apparatus for providing an easy-flow flushing system to flushing out an engine and an out-drive. The easy-flow flushing system may include a cap with a tubular member, a capping member, and a sleeve. The tubular member may include a first outer surface, an inner surface, a coil circumscribing the tubular member to urge a sleeve to a closed configuration, an opening along the first outer surface, and a ball bearing seated in the opening. The capping member may be coupled to the tubular member and the capping member can include a capping member end and a sealing ring disposed along a second outer surface. The sleeve may be coupled to the tubular member. The sleeve may include an inner surface, where the sleeve is formed and shaped to slide along a portion of the first outer surface of the tubular member.