fuel pump vs/ carb question.

Working on my YF carb is teaching me as i go i guess. I would like to ask some newbie question that maybe im just not understanding.

Where does excess fuel go from the carb? there is a line from mine going back to the tank, but one guy told me that there was no need for a return line. He said that when the float shut the fuel off the pump quit moving fuel.

Is this right? Mechanical pump quits??

On the carb the return line to the tank is right beside the inlet isnt it? Then a vent tube off to the side at the top of the carb, going to charcoal canister, right? Just making sure i have this right in my mind.

Thanks for bearing with me. What better to learn on than a Jeep! R)

 

Yes, if there's no return line, when the float bowl is filled, there's no flow anywhere. The pump builds up pressure, and the float admits fuel as needed.

Some return lines come from an extra nipple on the fuel filter. The vent line to the canister is only for vapor - there should be no liquid fuel in the vent line or the canister. You may not have a return line.

 

About dual outlet fuel filters.... does one side open AFTER back pressure is seen? If so, the mechanical fuel pump doesnt ever stop moving fuel, right?

 

I don't know if that nipple is open or if there's a valve of some kind in the filter. I'll cut one open someday.

The fuel flows continuously from the tank to the pump and back - this keeps the fuel cooler and prevents vapor lock (as I understand it).