Fuel Pump Vent?

[d3fiant1]

I'm unfamiliar with this third port on my mechanical fuel pump. I'm assuming is a vent from the pump to the crankcase filter. My question is, is this hose necessary? The original aircleaner assembly is long gone so I was planning in using an aftermarket crankcase filter, but I'm not sure if I should cap this "vent". Any Ideas?

 

[oBanion]

That 3rd nipple is just open to the crank case, thus making it a crankcase vent going into the breather there. It's no necessary with a breather already in the valve cover and of course a functioning PCV system.

 

[slantsixdan]

oBanion is not correct. Read this post for a detailed explanation of what you are seeing.

 

[d3fiant1]

oBanion is not correct. Read this post for a detailed explanation of what you are seeing.

Thank you for the explanation. Explains why I burned half a tank of gas on a 20 mile cruise. Looks like the hunt is on for an air cleaner housing.