Cooling system for outboard motor

An outboard motor comprising a power head including a four-cycle, internal combustion engine, a housing unit depending from the power head, a lubricant tank for the engine disposed in the housing unit, an exhaust conduit arranged to discharge exhaust gases from the engine, the exhaust conduit extending through the lubricant tank and at least a portion of the exhaust conduit extending lower than a bottom of the lubricant tank, and a cooling system arranged to cool at least the lubricant tank and the exhaust conduit with coolant, the cooling system including an inner coolant pool surrounding the portion of the exhaust conduit, and an outer coolant pool surrounding the inner coolant pool and the lubricant tank, and the cooling system supplying the coolant to the inner and outer pools.

An outboard motor comprising a power head including an internal combustion engine, a housing unit depending from the power head, and an exhaust system arranged to discharge exhaust gases from the engine, the exhaust system including an exhaust pipe connected to the engine and an expansion chamber disposed downstream of the exhaust pipe, the housing unit including a tubular section to define a coolant pool surrounding a portion of the exhaust pipe, the tubular section having a portion defining a bottom of the coolant pool, and the portion of the tubular section being disposed in proximity to a top end of the expansion chamber.

An outboard motor comprising a power head including an internal combustion engine, a housing unit depending from the power head, and an exhaust system arranged to discharge exhaust gases from the engine, the exhaust system including an exhaust conduit having an outlet arranged to open to a space within the housing unit, the housing unit including a portion forming a water pool surrounding the exhaust pipe, the housing unit defining a water discharge pathway through which the water in the water pool is discharged, and the housing unit further defining a dividing wall separating the water discharge pathway from the space.