Patent ID: 6921307

Claim:
An outboard motor comprising a housing unit adapted to be mounted on an associated watercraft, an internal combustion engine disposed above the housing unit, the engine defining a first exhaust passage communicating with a combustion chamber of the engine, the housing unit defining a second exhaust passage communicating with the first exhaust passage, the second exhaust passage communicating with an outside of the outboard motor through an exhaust discharge port formed at a portion of the housing unit, a primary air delivery unit arranged to deliver air to the combustion chamber, the primary air delivery unit having a throttle valve, a secondary air delivery unit arranged to deliver supplemental air to the combustion chamber, the secondary air delivery unit coupled with a portion of the primary air delivery unit at a location downstream of the throttle valve, and an air intake device communicating with the secondary air delivery unit and either the first exhaust passage or the second exhaust passage, the air intake device including a one-way valve connected to the secondary air delivery unit and at least one of the first and second exhaust passages so as to allow at least a portion of the supplemental air to enter the first or second exhaust passage and to inhibit exhaust gases from moving beyond the one-way valve.