E3 spark plug inconsistency

I had a friend give me a set of the E3 plugs. I had new Autolites in my cars so I thought I would use 'em in the lawn mower. Put one in and mower died halfway through the front yard. Took it out and replaced it and finished the lawn. A week later when it was time to mow the mower wouldn,'t start. So, I took the plug out and put in the old used Autolite which is still running years later. All eight of of those junk gimmicks went directly to the trash. So, I wouldn't run that junk in my mower either, even though I tried!