You get in trouble if you look at this "too simply."

        If there is a local hot spot, like around the spark plugs, the water can boil in just that spot. The rest of the water will be considerably cooler, likely well below the boiling point. The local boiling will remove an enormous amount of heat from the hot spot. The steam bubbles will collapse quickly as they move away from the hot spot and transfer the heat into the surrounding water.

        It is kind of like dropping a red-hot bolt into a bucket of water.

        Bill Dube'