There's another, somewhat simpler fix that only involves a couple of T fittings and a short piece of tubing. Install a tee on each side of the fuel pump, one in the inlet line and another on the output to the carburetor, and join the two lines with a short piece of tubing. Here's the trick- - - -install a bushing resembling a carburetor main jet into the bypass line with a TINY hole in it, like maybe .010" or so. It won't pass enough fuel to interfere with normal running, but once the engine is shut down, it will prevent pressure buildup in the fuel line from the pump to the carburetor by bleeding the pressure back to the pump inlet.
Jerry
