Need Help with a New Holland LS55 with Kohler CV20S engine. No start

I've owned this machine for 3 years and never had a problem until the other day. Went to start it, turned the key and nothing. I had just cut my grass 5 days earlier and had no problem. I turn the key and nothing happens except for that I hear a "click" up in the carb area. Here is what I have learned so far in my troubleshooting efforts: Battery....measures 12.4 volts across it. Ignition....I am getting 12 volts to the ignition switch and I am getting 12 volts out of 2 of the wires when I turn the key all the way over ( I am assuming that is good). I am getting 12 volts to the solenoid from the big red cable coming from the battery. There is also a small red wire connected with the big cable. There is another smaller wire connected to the solenoid but I am not sure what that is for. QUESTION 1: Should there be a DC voltage there when I turn the key over? QUESTION 2: Would the oil sentry/ sensor switch, if bad, keep it from starting? ( oil is full )

I checked all the fuses I could see and all were good. The PTO knob is in the right position to start. Not sure where to go from here. My grass is like a jungle. Any help would be greatly appreciated.