Home › Forum › Ask A Member › Johnson CD-13 trouble shooting. › Re: Johnson CD-13 trouble shooting.
Ask yourself this – why is it that the motor should die when the lever is moved to the ‘Stop’ position? Sure, the carburetor is completely shut down and the timing is fully retarded – but the ultimate reason is that the kill switch is engaged in that position. The kill switch shuts off the spark to as you push it toward ‘Stop’. ETA: No it doesn’t – see Mumbles’ comments, below.
So if it continues to run, there are a couple of possibilities. Either the kill switch is defective – not killing the spark, or there are hot spots in the combustion chamber(s) (carbon, hot plug tip, etc.) that continue to ignite mixture in the absence of spark, causing what’s known as run-on.
Hook up a timing light or other spark tester, and see if the spark goes away when you try to stop the engine. If it doesn’t, the kill switch is bad – if it does kill spark, and it still runs-on, I’d decarbonize the motor.