Mtd riding mower will not start?

I bought a used mtd riding mower and I repaired everything on it myself. I put new wiring in it and wired it up. The only wires that I ran in to trouble with were the reds and oranges. Other than that I am in good shape. I also put a new spark plug in it and bought a new battery with a new starter solenoid. I even replaced the ignition switch and the ignition wiring harness. It has pretty much been redone. Why is it not powering on? What should I check?