[Gasoline Fumes]

You might cause excessive wear to the pump and I'm guessing it will be very hard to restart after running the pump dry. Ideally you'd convert the existing shutoff to only draw those 2 amps to shut the engine down. Or convert it to a mechanical shutoff. Less ideal would be to cut off the air going into the engine to shut it down. Just be sure whatever you use can't get sucked into the engine!