I was all excited about the description, turns out you were talkin' bout the carb...oh well.
I'll go out to the garage and check but like you said, two are connected to each other; the large one is for the fuel, and the remaining are for venting the carb. Just run clear tubing from the nipples away from the carb. Some have run them up and others like myself just run them down with the carb overflow tube.
Yup, just vents with generic clear tubing from Lowes.