1972 Evinrude 65hp wonbt shut off HELP

"I have a 1972 Johnson 65hp th

"I have a 1972 Johnson 65hp that won't shut off. I turn the key to the off position and pull it out and it just keeps on going. It starts and runs like a top. I'll start it, turn the key to off, pull it out and it will rev in neutral at low rpms then after about 10 seconds it will rev to high rpms and shift itself into gear, forward or reverse usually forward, the whole time the neutral shift button is pushed in. I eventually have to disconnect the gas line and let it run out of gas to shut it off. I have no idea what's wrong. PLEASE HELP!!!"

"Check the kill circuit wiring

"Check the kill circuit wiring which is.....

Black wire from powerhead ground to powerpack.

Black/Yellow wire from powerpack to one of the "M" terminals of the ignition switch, the raised "M" terminal if it exists on the switch.

Black wire from the other regular "M" terminal of the ignition switch to ground.

When key is OFF, the two "M" terminals are connected which grounds the powerpack and kills the ignition.

When key is ON, the two "M" terminals ARE NOT connected and the ignition is enabled."