Exhaust system for marine propulsion

摘要

A number of embodiments of outboard motors including external expansion chambers for the exhaust system that are contained within the powerhead externally of the engine and internally of its protective cowling. In some embodiments exhaust gases are delivered to this external expansion chamber through a flexible conduit and in others through internal passages of the engine and outboard motor construction. In some embodiments the exhaust gases are discharged from the external expansion chamber to the atmosphere through an above the water exhaust gas discharge and in other embodiments the external expansion chamber functions only as a Helmholz resonator.