Fitting without hose?

[novi_4u]

I'm buying a boat with a 2005 Mercury 200XL Saltwater Carb. series. I noticed that a fitting (close to started) is open without a hose? Any idea about this fitting? Thanks in advance.

[boatmangc]

It's an air vent to allow warm air to enter the carberator venting.
Thank the EPA
It belongs there

[novi_4u]

It's an air vent to allow warm air to enter the carberator venting.
Thank the EPA
It belongs there

Do you know is this fitting is related to oil injection system?