One thing that happened to me on my Toro Z453 mower was when I purchased a new battery they gave me one that had the positive and negative termianls on the opposite side of my original battery but it fit into the holder. Well, it displayed the symptoms you discussed. I finally doing testing...
Recently, my mower was stopped after mowing and when I pushed in the PTO button apparently it did not go all the way down and I did not notice as it appeared the blades stopped turning and turned off the ignition switch. Now after it cooled off, it just clicked when trying to start the mower to...