Water line-intake manifold

[feyd]

if you look at the intake manifold where the carb bolts on, above the two main holes for the carb there's one small hole where water runs...it goes throught th e gasket and the riser and the other gasket into a small pocket on the bottom of the carb.

What i want to know is, is this for cooling of the carb or engageing the the choke? :confused: