HELP! I replaced the wiring harness and control box on my 1976 Mercury 850, and now the motor will not turn over using the key. The key does however engage the choke. I jumped started the motor, in which the key had to be in the "On" position for it to start, and the key also turned the motor off, but it just wont turn the starter over. I am at a loss. Please, anyone out there with a clue??