Patent ID: 6055970
Filing Date: 2000-05-02
Classification: F02B,F02D

Abstract:
An outboard motor having a power head and a lower unit extending therebelow, an internal combustion engine positioned within a cowling of the power head and having an output shaft extending generally vertically downward to said lower unit and arranged in driving relationship with a water propulsion device of the motor, the engine operating on a four-cycle principle and having at least one combustion chamber, an air/fuel charging system for delivering air and fuel into said combustion chamber for combustion therein, and an exhaust system including an exhaust passage leading from said chamber to a generally vertically extending main exhaust passage, said main exhaust passage extending to an exhaust guide positioned below said engine, an exhaust passage leading through said exhaust guide from said main exhaust passage to an expansion chamber positioned within said lower unit, and an exhaust gas discharge provided from said expansion chamber, and a feedback control for adjusting the ratio of air and fuel supplied to said combustion chamber, said feedback control including a combustion condition sensor mounted to sense exhaust gas flowing through that portion of said exhaust system above said exhaust guide.