Fuel pump question

[j4ivi35]

On the fuel pump in the pic im not sure what the hole in the green square is for? I know it not the inlet or outlet. Im thinking its just a vent from the crankcase but im not sure where it would go to? Its off a merc 140. Thanks in advance for any help.

 

[Bt Doctur]

Re: Fuel pump question

that should have a fitting that goes to the carb.it`s a vent line for the diaphram and uses a clear line. It also is a indicator when the diaphram fails.If you see liquid in it, the fuel pump has failed and needs replacement.