The solution is to run the motors out of gas. Don’t fill them or pour the unused gas out. When the job is done, let the motor run until the gas runs out.
My outboard motor dealer advises me there is sensor that cuts off the fuel injection pump before it runs dry on my 2008 fishing motor. He recommends Sea Foam to be added to the tank of this motor.(no he does sell Sea Foam, the O'Reily Automotive Stores do sell it)
He charges $85 per hour for repairs, I tend to follow his directions.
BAD IDEA OR ADVICE! Running a small engine out of gas is extremely damaging to the cylinder and piston! The run way too lean for too long before the gas and oil finally runs out. In 4 cycles, it is also very damaging. When they lean out, they exceed normal exhaust gas temperatures. This burns valves, damages heads and even can cause detonation. (Blow holes in the top of the piston) Doing this will trash a motor faster that running it on 10% Ethanol by any means!