If you can use a piece of tube to blow air through the breather pipe, you can clear the tube with a couple of puffs. I suggest you blow it downward into the valve chest if you can.
I'm doubtful that a Briggs engine actually stopped due to a loose plug lead, unless the lead literally fell off the spark plug. There may be a more subtle problem here, but if so, it should make itself known as you move forward.
