Patent ID: 8038493

Claim:
A marine propulsion device, comprising: an engine comprising a cylinder block and a head; a plurality of cylinders defined by said cylinder block; a plurality of combustion chambers defined by said head, each of said combustion chambers being disposed proximate an associated one of said plurality of cylinders; an exhaust manifold; a plurality of exhaust conduits connected in fluid communication between said plurality of combustion chambers and said exhaust manifold to direct a flow of exhaust gas from said plurality of combustion chambers to said exhaust manifold; a catalyst housing to direct said flow of exhaust gas through a catalyst device; an exhaust passage connected in fluid communication between said exhaust manifold and said catalyst housing; a first channel to direct a coolant to flow in thermal communication with said plurality of exhaust conduits; a second channel to direct said coolant upwardly and in thermal communication with said exhaust manifold; a third channel to direct said coolant downwardly and in thermal communication with said exhaust passage; and a fourth channel connected in thermal communication with said catalyst housing.