Explorer wont start

I have a 92 explorer sport I just put a new motor in. I got it off of ebay listed as bad motor ( it was ) and got a junk motor that ran. I hooked it all up and it would not start. My friend said the starter was bad, it just did the one click deal when you try and start it. I then replaced the relay and the battery. Hooked it all up and still just one single click when I tried to start it. I checked all ground connections on everything and cleaned the posts and cables but with no luck. It just does one click nothing else. Could it be the cable that everyone was talking about or could I have gotten a bum starter? Can you help me out? Thanks, Gary

You should have tried to jump it with another known good battery before you went and spent the money on a new battery. I would remove the starter, keep the wires hooked up to it, and see if it will spin by turning the ignition key just like you would if you were starting the vehicle. If the starter spins, something in the motor is binding. If the starter just "clicks", replace the starter. Hope this helps!

Mike