I have the same issue when I attach to the red hot wire and make a ecticric toaster wire it sparks why?What went wrong may be you hooked up a "hot wire" to ground and made an electric toaster wire. Follow above routing should cure. Replace or splice proper gauge wire where burned.
I'm just going to give you a little bit of background information I bought a Murray 40 inch select model number 405-000x8g used in January and when I first got it it would not want to start every single time sometimes I would have to Rock It and then I ran over something in the yard a cement Boulder after that a whining screeching noise would come from underneath my feet so I replaced the motion drive belt and then it just wouldn't start or it would click I knew there was a short somewhere because every time I push the clutch in I would hear sparking so I wanted to remove all the safety switches anyways so I removed all the doids and all of the wiring I only use the stuff that I needed so I did the solenoid the way you said in your reply I put the battery cabled to one big terminal the starter cable to the other terminal and then I have to little terminals I put one wire going to the ignition and then the other wire on the big terminal going to the ignition I have a black and a red wire coming from the Magneto or coming from the alternator I'm assuming the red one is the one that recharges the battery a wire is going from the red wire to the big terminal when I do it it just clicks it's not the solenoid it's not the starter I've replaced both of them and I've replaced the battery is there some kind of ground that I'm missing or should I connect the red and the black wires together and then run them to the solenoid I thought the black one went to the headlights though thank you for your help