My craftsman zts 7500 mower cranks over, but will not start?

It could be many things. First I would check to see if it is getting fuel, then check the spark plug for carbon and gap then the charge going to the spark plug.

There is a fuel lock (electrical cylinoid) at the bottom of the carburator that could be stuck. I had this problema and fixed it by taking it off and cleaning it. Started right up afterwards.

On mine both sparkplug lost compression. That means a total loss of the engine .and it wood run about 8 too 1 thousand too fix it.