what are you calling bad gas? Was it water in it or sediments, or something else wrong with it. May depend what was in the gas as to how far you will have to go, from changing filter to pulling gas tank and cleaning out. also are you saying the tank was half full when you filled it up with bad gas.
I got the pick up running. It was water in the gas, the tank was 1/2 full before i put the 3 or 4 gallon in. I could not find an inline fuel filter even checked with auto supply store, one was not listed for the pick up.
I took the valve out of the pressure relief valve that is in the fuel rail on the right side of engine clamped a hose on it cranked the motor till i out back to clean gas.