Efi fuel return line size?
 

Good day,

What's the point of running a return fuel line smaller than the feed line? I was just wondering...

Some fuel is burned, as such the requirements for the return line are less than the feed.

In the case of an engine driven, mechanical pump there is also a secondary reason. The supply side is under vacuum, the return under pressure. It's much easier to push fluid through a line than it is to pull it.