Abstract: An exhaust system for a marine exhaust system includes two riser conduits, each being connected to a Y-pipe at an outlet end. An inner tube of each riser conduit directs exhaust gases through a catalytic converter assembly and into the Y-pipe. An outer tube surrounds each inner tube to define a cooling liquid passage between the inner and outer tubes to direct cooling liquid into one of the inlets of the Y-pipe. A bellows couples one of the riser conduits to one of the inlets of the Y-pipe. Each bellows surrounds one of the inlets of the Y-pipe and one of the riser conduits. To minimize reversion, the inner tube of each of the riser conduits extends into one of the bellows further than the outer tube of the respective riser conduit.

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 system for a marine exhaust system includes two riser conduits, each being connected to a Y-pipe at an outlet end. An inner tube of each riser conduit directs exhaust gases through a catalytic converter assembly and into the Y-pipe. An outer tube surrounds each inner tube to define a cooling liquid passage between the inner and outer tubes to direct cooling liquid into one of the inlets of the Y-pipe. A bellows couples one of the riser conduits to one of the inlets of the Y-pipe. Each bellows surrounds one of the inlets of the Y-pipe and one of the riser conduits. To minimize reversion, the inner tube of each of the riser conduits extends into one of the bellows further than the outer tube of the respective riser conduit.

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: 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 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.