Marine propulsion systems and intake air systems for marine propulsion systems

1. A marine propulsion system for propelling a marine vessel in water, the system comprising:

a marine vessel;

an outboard motor that is coupled to the marine vessel, the outboard motor having a first inlet that receives intake air for combustion and a second inlet located on the hull of marine vessel;

a conduit that conveys the intake air from the second inlet on the marine vessel to the first inlet on the outboard motor, wherein the second inlet extends through one of a port and a starboard side of the marine vessel;

wherein the outboard motor is enclosed by the marine vessel and wherein operation of the outboard motor creates a negative pressure that does not affect pressure of the intake air received by the second inlet; and

an adapter that connects the cooling air conduit to the outboard motor, wherein the adapter engages the conduit with the outboard motor in a releasable snap-fit connection;

wherein the outboard motor has an opening that receives the adapter, wherein the opening on the outboard motor is sized slightly larger than an outer diameter of the adapter, and wherein the adapter is received by the opening in the snap-fit connection;

wherein the opening on the outboard motor defines at least one channel and wherein the adapter comprises an appendage that is flexible radially inwardly to fit within the channel; and

wherein the appendage springs back radially outwardly to engage the channel in the snap-fit connection.

2. The system according to claim 1 , wherein the marine vessel at least partially surrounds all sides of the outboard motor that are above the water and further comprising a hatch that provides access to the outboard motor.

3. The system according to claim 1 , comprising a protrusion extending radially outwardly from the appendage and engaging a recess in the top cowl when the adapter is rotated with respect to the top cowl.

4. The system according to claim 3 , wherein the adapter is threaded for engaging with the conduit in a threaded connection.

5. The system according to claim 1 , comprising an air filter connected to the conduit.

6. A marine propulsion system for propelling a marine vessel in water, the system comprising:

an outboard motor having an internal combustion engine;

an inlet on a front of the outboard motor, wherein the inlet receives intake air for combustion in the internal combustion engine and for cooling the internal combustion engine;

an intake air manifold that receives intake air from the inlet and conveys the intake air from the front of the outboard motor to a rear of the outboard motor;

at least one front air inlet hole in the intake air manifold that distributes the intake air for cooling the outboard motor;

a flywheel cover disposed beneath the intake manifold and having at least one air inlet hole that receives the intake air from the front air inlet hole in the intake air manifold; and

at least one rear air inlet hole located aft of the front air inlet hole in the intake air manifold, wherein the rear air inlet hole distributes intake air for combustion in the outboard motor.

7. The system according to claim 6 , further comprising a top cowl located on top of the internal combustion engine; and

an air intake duct and rear cowl disposed on top of the top cowl, wherein the intake air manifold is defined by the top cowl, air intake duct, and rear cowl.

8. The system according to claim 6 , further comprising a lower air intake tray defining the at least one rear air inlet hole, the lower air intake tray deflecting intake air downwardly into the rear air inlet hole for combustion.