14 HP MTD riding mower not starting?

This mower has sat out beside a barn for at least 6 years, and was then given to us. I've replaced the solenoid, and that was part of the problem with trying to turn it over. I dumped out the old gas and cleaned out the tank, filling it slightly with new gas. Replaced the fuel line coming from the tank to the fuel filter, which I replaced as well. Removed and disembled the carburetor, and let all the parts soak in carb cleaner for an hour. The mower still would not hit. I loosened the pilot screw, and now am getting a hit/pop every 2 or 3 seconds, but it's not firing completely up. Even spraying starting fluid in the intake manifold isn't working. What else do I need to check or do?