Small Engine Troubleshooting Problems? Ask a Mechanic Now.
!! Was not readied before delivery? Do you have a voltmeter to test with? Model number? Rider mower? Do you hear click from the fuel solenoid in the carburetor if you flip key on and off? If not , the keyswitch has no voltage. Battery can be dead, or the cables need to be revisited, to be sure they are clean and tight, and the plastic cover removed before cable was installed.
Did you get it going?