Do you have the body of the plug body grounded to a good ground while pulling away on the cord?
I cut two acres from the sixth grade (1976) until the summer after the twelfth (1982) with a 1964 push mower my dad bought new while in the U.S. Air Force. I had to work on that puppy each and every time before I used it! Pulling the rope out was a common issue (so do not do that!)
Pop kind of saw that I was joining the U.S. Army (Rangers) and he showed up with a brand new 8 hp "Hahn" rider (still a pull start)! Knowing he would be taking over the lawn duties. I rode it that summer with no problems.
Since then I have restored it with a 12 hp 'lectric start.
So I reckon the only part of that story that may have helped you was the "Do not pull the rope out"!
I feel for you, I hope you are not working on it out in the cold. Ranger school taught me to not be cold whenever possible (I froze my tail off), I keep three plus coats in each of my Jeeps at all times!
Keep us posted, we like happy endings.
Images (Click to enlarge)
Sunday, February 5th, 2017 AT 7:20 PM