[Jack21]

Low $$ solution. Fram makes a fuel filter with 3 hose connections, 2 ea., 3/8" inlet & outlet, and 1 ea., 1/4" outlet. Install between pump and carb. Plumb the 1/4" outlet to your return line. Install a short piece of brass rod in the return line drilled with a 1/16" orifice, and you're done.

Neither pump or carb are affected with engine running, but pressure is bled off when engine is shut down.

If you're getting too much pressure when engine is running, install a pressure regulator between pump and carb to keep pressure in the 6 - 7 lb range at the carb.