I let my family borrow my blaster while I was working and they put straight gas into the engine. I bought a new spark plug today & switched them out , drained the gas and put the right ratio in & it only starts for maybe 5 seconds and then dies out again. And once i tried it again, it stayed on longer but it would rev up by itself. What else should I do? Or is the whole piston/rings f*cked ??