I bought a used snapper lawn mower. When I bought it, there was no key and the guy had used a screw driver to start it. It worked for a long time but then was stripped out. I bought a new ignition and put it in. Now there is nothing, it won't turn over. Any ideas? Thanks

Check the back of the old switch , compare to new one make sure the terminals are marked the same.was this the replacement switch , or did you just make sure it had the same amount of spades ?
Luck

The terminals are marked the same. I bought the ignition at a snapper dealer. The battery is brand new and fully charge.

Check the plug make sure none of the connectors pushed out when you plug it in.
Might also check solenoid.
Luck