First, I would like to thank all of you for your replies! I started going through the switches, (PTO, Brake) found them all to be good after checking continuity on a multimeter. I then looked at the starter relay/solenoid and decided to check that. At first, I didn't get anything after performing a little test I learned on an YouTube video. I checked the voltage of the battery I was using and found it to be almost dead! Bear in mind this is the NEW battery I spoke of in my first post. Well, luckily I have a Bolens lawn tractor to work with too and I knew the battery in that was good. So I pulled it out of the Bolens and did my little test with that battery. Sure enough, the solenoid "clicked" and showed continuity. I assembled everything back together and decided to try and start it using the battery from the Bolens. Sure enough, it started without the assistance of a jump. Released the brake, it stayed running. engaged the PTO lever, it stayed running. So it wasn't a safety switch or relay after all. Moral of the story, "Start ALL electrical diagnostics at THE BATTERY". Also, never buy the cheapest battery. Spend a little money as you will save it later not buying aspirin to cure all your headaches. Once again, Thank You all for your input!