1990 30 OMC cannot shut off power

" I was out on the lake two da

" I was out on the lake two days after replacing the alternator, I tried to shut off the motor but it continued to run. I had to pull the coil wire to shut it off. With the key in the "off" position, I still have power as if it is in the "on" position After a little troubleshooting, I found the key switch checks ok. I pulled the alternator off, removed the purple wire marked "ignition" and everything worked correctly. Is there something bad in the alternator? or some other wiring problem? If there is a diode in the purple wire circut that went bad, where would it be? Thanks for any input. "

"I had the same problem on my

"I had the same problem on my 4.3, and found someone else with the same problem with a 3.0 on another forum. Both were the same. The battery cable on the starter solenoid was loose and had turned enough to make contact with the coil terminal. I don't know why his was loose, but mine was because I had just replaced the battery cable and forgot to tighten it. I re-routed the battery cable over the cooling hose to prevent it from turning if it loosens up again."