Abstract: A marine propulsion system has an exhaust conduit conveying exhaust gases from an internal combustion engine. The exhaust conduit has a dry portion and a wet portion located downstream of the dry portion. Cooling fluid enters the exhaust conduit to cool exhaust gases flowing through the wet portion. A bypass conduit is connected to the exhaust conduit and conveys a portion of the cooling fluid away from the dry portion to thereby decrease reversion of cooling fluid into the dry portion.

Abstract: An apparatus for separating solid material from cooling water in the cooling system of the engine block of a marine engine. The engine block comprises a plurality of cylinder bores surrounded by a cooling passage through which cooling water is pumped. The bottom portion of the block includes a drain outlet that communicates with the cooling passage and a tubular separating member has a first generally horizontal section that is sealed within the drain outlet. The tubular separator also includes a second section that is located within the cooling passage and extends downwardly from the inner end of the first section and is located between two adjacent cylinder bores. The lower end of the second section is closed and a port is provided in the side of the second section adjacent the closed end and facing toward one of the cylinder bores.

Abstract: A drain valve assembly for automatically draining water from a cooling system of an inboard marine engine when the ambient temperature drops to a preselected value. The drain valve includes a cup-shaped base having a group of inlets connected to portions of a cooling system of the engine to be drained, and the open end of the base is enclosed by a cover. Each inlet defines a valve seat and a sealing piston is mounted for movement in the base and includes a series of valve members that are adapted to engage the valve seats. An outlet is provided in the sidewall of the cup-shaped base. The valve members on the sealing piston are biased to a closed position by a coil spring and a temperature responsive element interconnects the sealing piston with the cover. The temperature responsive element is characterized by the ability to exert a force in excess of the spring force of the coil spring when the ambient temperature is above about 50.degree. F., to thereby maintain the valve members in the closed position.

Abstract: An apparatus for separating solid material from cooling water in the cooling system of a marine engine. The apparatus includes a hollow member or housing having an inlet to receive cooling water and having an outlet. A drain opening is located in the housing above the bottom surface of the housing and is connected through a suitable conduit to a temperature responsive drain valve. A generally J-shaped tubular member is disposed in the housing and has one end connected to the drain outlet while a second end is slightly above the bottom surface of the housing, out of alignment with the inlet. When the drain valve is open, water will drain through the housing to the drain outlet, while solid debris will collect in the bottom of the housing beneath the second end of the tubular member.