Zero Turn Mower. I'm stumped.

Well, after all this time, it was the gas. I disconnected all the hose, blew and flushed the tank and hose and filter out, emptied the carburetor bowl. Put it all back together and put most of a remainder of a gallon of True Fuel I had in the tank and dumped a little in the carburetor and da beeotch popped off and ran as good as it ever has. I even cut some with it. LOL This is good, because now I can use it for the more heavy cutting and save my Troy Bilt for all of the grass around the house. Thanks for the ideas fellers.