return line on carb motor

I'm rigging a 2.5 200 Merc (WMH carbs). The previous motor was EFI, so it has a return line already. Will be using a Holley Red pump.

1. Has anybody run a return line to the gas tank?
2. How did you plumb it?
3. Hose sizes, etc.?

Mine came off the fuel pressure regulator to the tank 5/16 on this set up because that's the size of the tank fitting. No pressure issues with a Bosch efi pump. I used to switch to a 260 and was too lazy to switch pumps. No problems so I've stuck with it.

I had to add a return to a plastic tank once. Found a thick place , drilled a hole smaller than the fitting , and forced the fitting to thread itself. Backed it out and reinstalled with Teflon. But it sounds like you have a fitting for the return.

You can change the regulator fitting to match the return fitting and go with that size hose. Mike

Been doing it for years. Bypass regulators are a bit more expensive but are much better quality than a dead head regulator. Mine requires a 3/8" return. I run a Bosch EFI pump like Mike. Works great. Do yourself a favor and buy a Carter pump not a Holley. Even better is the Bosch. Mine supported a carb'ed 280 @ 8700.

In a pinch, you can remove the fuel sender in the tank and drill and tap a 1/4 pipe thread into it to put a fitting in.

Orfice the return line after the carb,check pressure at the carb with a temperary low pressure gauge.change the orfice to get your proper pressure. Empty 22 magnum shell caseings with different size holes drilled through the head worked for me

I like Dalton like the carter pumps also. Work well. Mike.

use a cartridge fuel filter before the pump and plumb the return line back to the suck side of the filter ......