When I stick key in ignition I get nothing. I have already replaced the battery, spark plug, still nothing.

Barcroft

We are going to need to follow the 12 vdc down stream to the starter. You need a 12 vdc tester. Measure the power between the black and red battery terminals, about 12 vdc right? Follow the red cable to the ignition switch and test that terminal going into the switch, 12 vdc. Find the wire that goes from the ignition switch to the starter solenoid (looks like a black beer can with several cables). When you turn the key you should get 12 vdc going down this cable and also coming out of the other cable on the solenoid. I am going to stop here for now because I'm betting you have already found something that you need to bring back to us.