Patent ID: 8650864

Claim:
An exhaust system for a marine engine, comprising: a combination of a liquid-cooled exhaust manifold assembly and a liquid-cooled catalytic converter assembly, which liquid-cooled exhaust manifold assembly comprises a plurality of tube assemblies, each of said tube assemblies comprising an exhaust tube extending from a mounting plate secured to the marine engine to the catalytic converter assembly and an outer tube surrounding the exhaust tube, each of the outer tubes being spaced from one of the exhaust tubes and defining a cooling cavity therebetween, liquid being supplied to the cooling cavity via a feed tube and being collected in a collector and passed through a collector outlet to cool the outside surface of the outer tube to maintain the outside temperature of the outer tube below a predetermined temperature, and liquid being supplied to and from a fluid passage surrounding a catalytic converter housing to cool and maintain the outside surface of the catalytic converter assembly below a predetermined temperature wherein each of the exhaust tubes passes through the collector and into the catalytic converter assembly and each of the outer tubes extends into the interior of the collector.