Repairs I've bought 1 mower in my life and don't want another. Help please!

So I have a 6.5 HP Dura Force Model 10323 (15 years old) and I'm troubleshooting. I already rebuilt the carburetor although I don't think that was the issue. It will not start. The last 3 times I used it it stopped after 15 minutes, but would restart a few hours later. Now it will not start at all.

I was wondering if there were any tips for testing the ignition without getting zapped?

Repairs I've bought 1 mower in my life and don't want another. Help please!