Abstract: An exhaust conduit for a marine exhaust system includes an inlet end portion connectable to an exhaust manifold, an outlet end portion that directs exhaust gases toward an exhaust system outlet, a catalytic converter assembly arranged between the inlet and outlet end portions, and inner and outer tubes. The inner tube directs exhaust gases from the exhaust manifold to the catalytic converter assembly, and the outer tube surrounds the inner tube to define a cooling liquid passage between the inner and outer tubes. A flange is secured to the inner and outer tubes at inlet ends thereof, the flange being connectable to an outlet of the exhaust manifold. The inner tube has a uniform diameter between the flange and the catalytic converter assembly, and is welded to the flange independently of the outer tube. First and second welds join the inner and outer tubes to the flange at radially inner and outer faces, respectively, of a flange rim.

Abstract: An exhaust conduit for a marine exhaust system includes an inlet end portion connectable to an exhaust manifold, an outlet end portion that directs exhaust gases toward an exhaust system outlet, a catalytic converter assembly arranged between the inlet and outlet end portions, and inner and outer tubes. The inner tube directs exhaust gases from the exhaust manifold to the catalytic converter assembly, and the outer tube surrounds the inner tube to define a cooling liquid passage between the inner and outer tubes. A flange is secured to the inner and outer tubes at inlet ends thereof, the flange being connectable to an outlet of the exhaust manifold. The inner tube has a uniform diameter between the flange and the catalytic converter assembly, and is welded to the flange independently of the outer tube. First and second welds join the inner and outer tubes to the flange at radially inner and outer faces, respectively, of a flange rim.

Abstract: A heat exchanger for a marine engine has a housing with an internal cavity. Twisted tubes snake back and forth inside the cavity and carry a first fluid to cool a second engine cooling fluid flowing through the cavity. Each of the twisted tubes has a plurality of ridges to increase the surface area of the tube exposed to the second fluid. Dividers inside the cavity direct the flow of the second fluid through the cavity. The housing may have a removable cover to access the housing cavity.

Abstract: An exhaust system for a marine engine comprising liquid-cooled manifold and catalytic converter assemblies. Each assembly uses a separate cooling system to cool either the exhaust manifold or a shell inside which resides the catalytic converter. The housing or shell containing the catalytic converter uses water to cool an exterior surface of a water jacket to an acceptable temperature conforming to federal regulations. The liquid-cooled manifold assembly may use either water or glycol to cool outer cooling tubes surrounding exhaust tubes extending from the engine block to the catalytic converter assembly.

Abstract: An exhaust system for a in e engine comprising liquid-cooled manifold and catalytic converter assemblies. Each assembly uses a separate cooling system to cool either the exhaust manifold or a shell inside which resides the catalytic converter. The housing or shell containing the catalytic converter uses water to cool an exterior surface of a water jacket to an acceptable temperature conforming to federal regulations. The liquid-cooled manifold assembly may use either water or glycol to cool outer cooling tubes surrounding exhaust tubes extending from the engine block to the catalytic converter assembly.

Abstract: An exhaust system for a marine engine comprising liquid cooled manifold and catalytic converter assemblies. Each assembly uses a separate cooling system to cool either the exhaust manifold or a shell inside which resides the catalytic converter. The housing or shell containing the catalytic converter uses water to cool an exterior surface of a water jacket to an acceptable temperature conforming to federal regulations. The liquid-cooled manifold assembly may use either water or glycol to cool a jacket surrounding tubes extending from the engine block to the catalytic converter assembly.

Abstract: A combination exhaust manifold and catalytic converter wherein the catalytic converter is in the form of a removable and replaceable cartridge mounted within an opening of an exhaust manifold. This cartridge is supported within the opening of the exhaust manifold by sealing rings and retained within the opening by a removable fastener element.

Abstract: A combination exhaust manifold and catalytic converter wherein the catalytic converter is in the form of a removable and replaceable cartridge mounted within an opening of an exhaust manifold. This cartridge is supported within the opening of the exhaust manifold by sealing rings and retained within the opening by a removable fastener element.