When I try turning the key nothing happens. I can bypass the key by crossing the two lugs by the battery and the motor will turn over but does not fire. I checked the spark plug, it's OK but not getting fire to it. Where do I need to check next?

Hi,
I would say it is the key switch, though it could be another of the three safety switches are involved. I say what I said because of the lack of fire (you do have the switch turned "on" and the brake locked in "park", don't you?)
Peace,
Clarke