Abstract: A cooling system for an internal combustion engine of a marine propulsion system is provided with a poppet that is overmolded with a resilient sealing material to enhance its sealing capacity. As a result, the pressure within the internal combustion engine cooling passages can be maintained more accurately. Because undesirable leakage past the poppet is more successfully prevented by the overmolded poppet, the cooling system can more accurately regulate the temperature of the engine.

Abstract: A torsional damper is provided for an outboard motor and disposed between a flywheel and the engine of the outboard motor. The torsional damper is also shaped to be disposed within a cavity of the flywheel formed by a plate portion and a skirt portion of the flywheel. The torsional damper comprises an inner member that is attached to the flywheel, an outer wheel that operates as a spring mass, and a resilient central member that is made of an elastomeric material and disposed between the inner and outer members.

Abstract: A flushing device (30) for the cooling system of a marine drive (10) includes a housing (32) having an inlet (34) for receiving pressurized flushing coolant, an outlet (36) for discharging the flushing coolant to the marine drive cooling system, a pulsation chamber (33) between the inlet (34) and outlet (36), and a pulsation mechanism (40) in the pulsation chamber (38) and receiving the pressurized flushing coolant and imparting a pulsation movement thereto and delivering pulsating flushing coolant to the outlet (36).

Abstract: A driveshaft housing structure adapted for interposition between the powerhead and the gearcase of an outboard marine propulsion system. The driveshaft housing structure is integrally formed, and provides a driveshaft passage, a cooling water intake conduit arrangement, an exhaust discharge passage, a cooling water discharge passage, and an exhaust idler relief system. The listed components are formed of a series of walls which comprise a part of the integrally formed driveshaft housing structure, to provide a unitary one-piece cast structure eliminating the need to assemble an adaptor plate to the upper end of a driveshaft housing, as in the prior art. The unitary one-piece structure is constructed from lost foam casting of an assembled pattern which allows the various components to be integrally formed with each other.

Abstract: An air intake system for an internal combustion engine associated with the power head of an outboard marine propulsion system. The engine includes a vertical crank shaft and a flywheel mounted to the crank shaft above the engine block. An air manifold is mounted to the forward side of the engine, and includes an air inlet for receiving intake air. The air intake system includes an air flow path or duct defined by a series of walls, a rearwardly facing air intake opening and a discharge opening for supplying intake air to the air manifold inlet. The engine is enclosed within a cowl assembly, and the air intake opening is located toward the upper end of the cowl assembly interior. The walls defining the air flow duct are formed integrally with a flywheel cover for facilitating assembly of the air flow duct to the engine. The air flow duct minimizes ingestion of water into the engine and reduces engine noise in the boat.

Abstract: An evaporable foam pattern for casting a metal air induction manifold for an internal combustion engine. The pattern is formed from an evaporable foam material, such as polystyrene, and in the assembled condition the pattern is in the form of an elongated body member having a generally rectangular cross section. One end of the body member is enclosed by an end wall while the opposite end of the body member is open. One of the side walls of the body member is provided with a plurality of generally parallel slots which are elongated in a lateral direction with respect to the longitudinal axis of the body member. The pattern is composed of a pair of longitudinal pattern sections each being generally U-shaped in cross section and having abutting edges disposed on a parting line. An adhesive joins the abutting edges. The parting line between the pattern section splits the opening in the end of the body member and all of the slots are formed in one pattern section.

Abstract: An evaporable foam pattern for producing a cast metal head for a multiple cylinder engine. The assembled pattern includes an elongated block of evaporable foam material having opposed inner and outer faces. A plurality of generally circular head recesses are formed in the inner face and define the cylinder heads in the metal casting. The block is also formed with an internal passage including a group of annular chambers that surround the head recesses and channels interconnect adjacent chambers. The block also has an inlet which communicates with one end of the internal passage and an outlet that communicates with the opposite end of the passage. The pattern is composed of a pair of longitudinal pattern sections having abutted edges that are joined together by an adhesive. The heads, as well as the inlet and outlet, are located in one of the pattern sections, while the two sections in combination define the internal passage.