Exhaust device for a four-cycle outboard motor

Abstract

An arrangement is provided for the lubricating, cooling and exhaust systems of a four-cycle outboard watercraft motor. Coolant is drawn from the body of water within which the watercraft is operated for circulation through the engine cooling system. Subsequently, the coolant is brought into proximity with an exhaust pipe extending downwardly from the engine within an encasing member. After passing downwardly along the exhaust pipe the coolant is finally directed towards an exhaust gas expansion chamber and a cooling water jacket provided around the expansion chamber. In order to prevent any of the cooling water from splashing back up against an oil reservoir, also located within the casing, a cover is provided across the tops of the expansion chamber and its accompanying cooling water jacket. Coolant water or air may fill the voids separating the various components contained within the encasing. The arrangement is particularly effective in preventing the corrosion of the oil reservoir housing due to back-splashed coolant when the watercraft is operated in salt water; cooling the components contained within the encasing; and, minimizing heat transfer from higher temperature operating components to lower temperature operating components.

Dependencies are inferred from the claim text.