Patent ID: 6039618
Filing Date: 2000-03-21
Classification: B63H,F01N,F02B,Y02T

Abstract:
An outboard motor comprised of a power head and a drive shaft housing and lower unit depending from said power head, said power head containing a powering, four cycle, internal combustion engine and a surrounding protective cowling, a propulsion device contained within said lower unit for propelling an associated watercraft through a body of water in which it is operating, a transmission system for transmitting drive from said engine to said propulsion device, an expansion chamber formed in said drive shaft housing, an exhaust pipe depending from said engine into said expansion chamber for delivering of exhaust gases to said expansion chamber, an oil tank for said engine disposed in said drive shaft housing at the upper area of said expansion chamber and in proximity to said exhaust pipe, said expansion chamber communicating with the atmosphere through a below the water high speed exhaust gas discharge, an above the water low speed exhaust gas discharge formed above the normal water level, and means for communicating exhaust gasses from said engine to said above the water low speed exhaust gas discharge through a path that extends vertically above the level of oil in said oil tank.