I have a cub cadet z-series zero turn lawn mower...I cut grass earlier and happen to run out of gas so put more in and also added some oil that was needed. Tried to crank it and it sounded like it wanted to crank but would never turn over, so I put a battery charger on it and once I did that now nothing! Doesn't do anything now..no noise, nothing happens when I turn thekey...What have I done?!