Patent ID: 6632110
Filing Date: 2003-10-14
Classification: B63H,F01N,F02B,F02M,Y02T

Abstract:
An outboard motor comprising an internal combustion engine and a propulsion unit driven by the engine, the engine including an engine body defining a plurality of combustion chambers therein, and an exhaust system comprising an exhaust manifold defining a plurality of exhaust runners communicating with the combustion chambers, a merging portion in which the exhaust runners merge, and a common exhaust passage which receives exhaust gases from the merging portion, the common exhaust passage communicating with an expansion chamber configured to quiet exhaust noises traveling through the common exhaust passage, a valve disposed in the common exhaust passage and controlling a flow of exhaust gases therethrough, a catalytic treatment passage branched from the common exhaust passage at a position upstream from the valve, the catalytic treatment passage extending from the common exhaust passage to a catalytic treatment device so as to guide exhaust gases from the common exhaust passage upstream from the valve into the catalytic device, a throttle device configured to control the flow of air into the combustion chambers, a linkage arrangement connecting the throttle device to the valve so as to control movement of the valve proportionally to a movement of the throttle device, the linkage arrangement being configured to bias the valve to a closed position when the throttle device is in a position corresponding to an idle speed of the engine.