A marine engine has first and second banks of piston-cylinders, and first and second cooling water passages that convey cooling water in parallel alongside the first and second banks of piston-cylinders, respectively. A cooling water pump pumps the cooling water through the first and second cooling water passages. A first temperature-responsive valve is configured to discharge the cooling water from both of the first and second cooling water passages when the cooling water reaches a first temperature threshold. A second temperature-responsive valve is configured to discharge the cooling water from both of the first and second cooling water passages when the cooling water reaches a second temperature threshold that is greater than the first temperature threshold.

An engine includes a crankshaft extending in a vertical direction. A drive shaft is connected to the crankshaft and coaxial with the crankshaft. A water intake passage is connected to the engine. A water pump is connected to the water intake passage. The water pump includes a pump shaft. The pump shaft is eccentrically mounted with respect to the drive shaft and parallel or substantially parallel to the drive shaft. The pump shaft rotates according to rotation of the drive shaft.

An engine includes a crankshaft extending in a vertical direction. A drive shaft is connected to the crankshaft and coaxial with the crankshaft. A water intake passage is connected to the engine. A water pump is connected to the water intake passage. The water pump includes a pump shaft. The pump shaft is eccentrically mounted with respect to the drive shaft and parallel or substantially parallel to the drive shaft. The pump shaft rotates according to rotation of the drive shaft.

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 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 outboard motor includes an engine, a first cooling water passage to cool a first cooling target including the engine and through which first cooling water including water from outside an outboard motor body passes, a first pump to pump the first cooling water from outside the outboard motor body to the first cooling water passage, a second cooling water passage to cool a second cooling target different from the first cooling target and through which second cooling water different from the first cooling water passes, and a second pump to pump the second cooling water to the second cooling water passage.

An outboard motor includes an engine, a first cooling water passage to cool a first cooling target including the engine and through which first cooling water including water from outside an outboard motor body passes, a first pump to pump the first cooling water from outside the outboard motor body to the first cooling water passage, a second cooling water passage to cool a second cooling target different from the first cooling target and through which second cooling water different from the first cooling water passes, and a second pump to pump the second cooling water to the second cooling water passage.

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 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.

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.