boat wont shut off

I just bought a 1978 silverline with an outboard 90 hp Johnson (4 cylinder 2 stroke) when I turn the key to the off position the engine continues to run but it seems to be running on 2 cylinders. any ideas?

I don't know the age of the engine the model number is J90MLCTE
The engine is not dieseling
I would love to see an electrical print. How do I find one,

 

Is it dieseling? Because post '81 ignition should be CDI which would shut down when the power was killed. They won't run on like a magneto.

 

the ignition does not turn off the ignition it shorts it out ..suggest you check the wiring diagram and see if both banks are being cut off ....you dont say the age of the engine ..I have the manuals for the V4 90 as I had one until recently

 

I had a similiar problem with my inboard skiboat. I found the DC negative connection to the engine was loose.

 

If two modules are shutting off but the other two not, there is a problem with the wiring. It will be easier if you get a wiring diagram. The ignition shuts off by getting grounded.

 

I dont know the year of the engine. The model number is J90MLCTE
The engine is not dieseling.
I would love to look at an electrical print. How do I find one?

 

You can try the library first. There are several online services that sell wiring diagrams for anything you can think of

 

Sounds to me as though your key switch is bad. I had this problem before... I use to have to choke it till it dies... changed the key switch and problem solved.

 

This is likely the one you want.

Try here and there are others to select from.

http://bpi.ebasicpower.com/pc/SEL1302/OB-OMCSELOC