My understanding is there is a very small orifice that bleeds the vapor and a tiny amount of fuel but you still get more than enough fuel to run the engine. View attachment 1715941429
We did something similar to this when I raced outlaw karts with cr500 engines. We would put a carb jet in the return line otherwise it would starve the carb for fuel and just send it all back to the tank. Interesting how stuff crosses over.