Why isn’t fuel going to the carb?

The OEM return was only fuel vapors from the bowl vent on the OEM carb. There was a charcoal canister with flow check valve.
Maybe some do use this metal pipe for a liquid fuel return. My questions , Can all the fuel go that route? Will fuel pressure delivered from the pump push any fuel through the tiny orifice into the bowl? How long might it take to fill the bowl if there is no restriction in that return path?
You might answer some of these questions with a clamp on that return hose.