Is the fuel solenoid working? Is the kill switch working? I have seen engine where the kill switch stopped working and when the switch shut off power to the fuel solenoid it took the engine a few seconds to run the last bit of fuel out of the carb pick up tube. Try this. Hook a inline spark tester on the spark plug. Start the engine. Watch the tester. Does the tester stop as soon as you the switch or does it keep firing until the engine stops?
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