Return line, can it be smaller than the feed line?

RustyRatRod said
It CAN but it doesn't have to be. The size of the return line really has no effect on operation, because it's the return orifice that matters. This is why when I plump a fuel system with a return, I use a return style regulator and put it in the return line so it acts as the orifice. That way, you can use whatever size you want, including the same as the supply line and it does not matter.

There was actually a Barry Grant pump and regulator with a return line and that system used the return line as the restriction. I forget the part numbers of the stuff but I ran into several of them and had to change the return line to make them work.