Carter 2 bbl

I have a 69 barracuda with a 318 2bbl card. I rebuilt it and am having trouble getting it to idle smoothly. I was on Amazon looking at carburators and it appears this carb is for 70-73 318's. It has a plastic vent tube on top where the accelerator pump sticks up. Is there suppose to be a hose connected to this vent tube?
Thanks
Author: Mopardan