200 Johnson Ocean Pro

[Seafarer1]

Started my 2000 Johnson 200 Ocean Pro today today to winterize it. after three or four attempts the engine started but ran very rough and cut out several times. After warm up the engine would go from a slow idle to approximately 5000 rpm's on it's own and back to an idle. Lastly the engine ran up to 6000 rpm's and would not shut off. It continued to run even with the ignition switch turned off and the batteries switched off. What next?

 

[Chris1956]

Well, it sounds like the first thing to investigate is the grounding of the powerpack, to kill ignition. Usually it is the black/orange and black/yellow wires that kill ignition.

You might check the throttle linkage as well.

 

[Seafarer1]

Thanks Chris, If the engine was running hot would it cause the powerpack to act up like that and cause the rpm's to fluctuate and eventually run up high enough to where you couldn't shut it off ?
I did check the throttle linkage and all seems ok and haven't been tampered with.

 

[Chris1956]

The overheat sensor will kill spark to certain cylinders, which would cause the motor to run rough, however, I do not think it would cause the motor not to shut off.

 

[Faztbullet]

The overheat sensor will kill spark to certain cylinders, which would cause the motor to run rough​

Sorry but it will not do this...it will trigger SLOW in pack which limits RPM to 2500.. If engine got really hot it can "4 stroke" after key is turned off. If you sprayed excessive fogging oil in air breather it can cause RPM to raise depending on the brand.