probably the 1 faulty welded one out of a million.Once sold my Radial finn 400 to a guy,next meeting he was on about does not start,did the petrol etc questions-turned out he had put in a new plug,no spark,ok he said heres my spare new plug and still nothing,went and got old plug out of my mag Husky and first kick it started .What are odds of 2 dud new plugs?