Carb outlet
I had the same question for my homelite.
The outlet can be run into the inlet using a "T" fitting or you can just let it like it is. When you push the primer bulb, it will fill and if you keep pushing it, the excess fuel will just be expelled out the outlet. If you are a "button pusher" or a smoker, you may want to plumb it back into the inlet to keep from pumping fuel allover the place. Mine didn' leak after I stoped priming. I flew it with nothing connected to the outlet.
Garry