Re: 1988 140 johnson wont turn off?????
The stop circuit is: Black wire from powerhead to powerpack, Black/Yellow wire from powerpack to raised "M" terminal of the ignition switch, Black wire from the other regular Black terminal of the ignition switch to ground.
Key ON = No connection between the "M" terminals
Key OFF = A positive connection between the two "M" terminals.
If all of these wires are connected properly and have continuity, then I would suspect a bad circuit within the powerpack BUT although this has been known to happen, it is highly unlikely.