1978 70hp Johnson won't shut off with the key

[BonairII]

Just replaced the PP and got the motor running somewhat well. I went to turn off the motor and it doesn't shut down with the key....had to choke it to shut it down. This motor is new to me so I don't know if this is a new issue or was a problem before I bought it.

Been doing some reading here and have seen this can be caused by a bad ground. Is this likely the case for me? What's the easiest way to check for a bad ground?

Update: Just started the motor and also found out that the electric choke doesn't work after the motor is running, so I have to choke the motor manually.

 

[metriccrescentwrench]

Re: 1978 70hp Johnson won't shut off with the key

Go to the top of this forum to a thread called "top secret files". In there is a link to a site with some OMC wiring diagrams online. While your engine might not be included it should be similar enough to let you see what's going on.

There's a black/yellow wire coming from the powerpack(s) and ending up at your ignition switch. That wire is supposed to be grounded when you want the engine to shut off, apparently that's not happening. Check it at the ignition switch to see if it's grounded when the switch is in the off position and not grounded the rest of the time. If it's ok there then check it at the powerpack. If it's ok at the switch but not the powerpack you'll need to figure out where that wire is open.

As far as the primer solenoid, start checking at the keyswitch for that also. The purple/white wire gets +12 V when the key is pushed in. If it's ok at the switch then check at the primer solenoid.

 

[BonairII]

Re: 1978 70hp Johnson won't shut off with the key

I don't understand how the electric choke works to start the motor, but the becomes inoperable once the motor is running.