Exhaust emission control device for outboard motor

PURPOSE: To obtain specified exhaust emission purifying effect by disposing a catalyst of sufficient capacity in the case of leading a first exhaust passage from an engine to an exhaust air expansion chamber below the engine. CONSTITUTION: An engine 10 is disposed at the upper part of the casing of an outboard motor 1 fitted to a hull 2, and an exhaust air expansion chamber 29 is provided in a position below the engine 10. A first exhaust passage A for communicating the engine 10 with the exhaust air expansion chamber 29 is provided being opened into the exhaust air expansion chamber 29. A second exhaust passage B for communicating the exhaust air expansion chamber 29 with an underwater exhaust outlet 39 is further provided, and a catalyst 35 is disposed in the second exhaust passage B or the exhaust air expansion chamber 29, between the opening position of the first exhaust passage A and the lower end of the engine 10. The first exhaust passage A from the engine 10 is led to the approximately center part of the exhaust air expansion chamber 29 below the engine 10, and the catalyst 35 is disposed on either side of the first exhaust passage A. COPYRIGHT: (C)1993,JPO&Japio