MSD

After "fixing" my lawnmower, a process that involved scraping 1/8" of carbon buildup off of the inside of the head, snapping off two head bolts, reusing a damaged head gasket, and rebuilding the carburetor (I actually did this properly,) I soaked most of the engine in carb cleaner, and sprayed a liberal dose inte the carb itself. Starting it without an air filter and using 6-month-old gas (to which I'm fairly sure I added stabilizer last fall,) I discovered that to my surprise, flames shot out of the carb itself rather than out of the weak spots in the damaged head gasket. This was accompanied by the distinct popping of a backfiring engine, and to my disappointment, the entire mower did not go up in flames as I had expected. My current plan is to wait until after sunset and try again, as I expect the flames to be much more dazzling when not overpowered by direct sunlight.

My question is, what is the easiest way to make it stop doing this, and if that fails, what is the easiest way to blow up the mower in such a way that my mother will not expect me to fix it and instead buy another one (since we don't have a garage or shed to keep them in, we tend to buy an average of one mower every 18 months.)