1990 40hp Johnson won't stop running

[miscrap]

I have a 1990 Tracker Deep V, with the original Johnson 40hp engine. I had the boat out for the first time this season a couple weeks ago. When I got to my fishing spot I shut off the engine... but it kept running. I pulled the key out, but it still kept running. Figuring I had a bad ignition switch, I purchased a new one, and installed it yesterday. A few quick start/stops in the driveway seemed to indicate that the problem was solved. However, today on the lake, the engine again would not turn off. When I got back to the launch I pulled the safety, but the engine still continued to run. I had to pull the fuel line in order to put the boat back on the trailer.
I've done a bunch of searching, on this site and others, but most seem to refer to larger, inboard motors. I have a parts manual with diagrams, but have no idea where to look. The only wiring I've done since last season was to replace the am/fm radio in the console. All the wiring was done there, not near the engine. Can anyone tell me how to find the cause of this problem?
Thanks!

 

[miscrap]

Re: 1990 40hp Johnson won't stop running

Wow! Over 130 views and no one has an idea?

 

[Will Bark]

Re: 1990 40hp Johnson won't stop running

The only thing I can think of is that it's "deisling meaning it's running without the ignition by having glowing carbon deposits in the cylinders. Have you looked in the sparkplug holes to see if you have a lot of carbon buildup? Other than that some of the gurus will need to chime in with other thoughts. Good luck

 

[miscrap]

Re: 1990 40hp Johnson won't stop running

The only thing I can think of is that it's "deisling meaning it's running without the ignition by having glowing carbon deposits in the cylinders. Have you looked in the sparkplug holes to see if you have a lot of carbon buildup? Other than that some of the gurus will need to chime in with other thoughts. Good luck

Thanks for the reply, but it's not dieseling. I can drive the boat around the lake with the ignition turned off and the key out. It runs just like the key was in there and the ignition on.

 

[Will Bark]

Re: 1990 40hp Johnson won't stop running

Then you must have a power pack that is not grounding out when the key is turned off which is what grounds the power pack maybe a wire broken somewhere; again, the gurus with the wiring diagrams will need to chime in. Good luck

 

[boobie]

Re: 1990 40hp Johnson won't stop running

Check your black/yellow wire going all the way back to the pack. Also check the black wire coming off of the switch to make sure it's grounded. It could also be a blown diode in the pack not letting it ground out to stop it. Been there.

 

[miscrap]

Re: 1990 40hp Johnson won't stop running

FOLLOW UP: I found that when the engine doesn't shut off when the key is turned, if I lift the wires/cables coming out of the engine where they enter into the boat, the engine will stop. I don't have to lift them much, just 1/8 to 1/4 of an inch. I'm lifting them where they enter the boat, not at the engine. I assume that means that a wire is making contact with the metal of the boat. The problem is, the wires run behind the gas tank when they enter the boat, so it's impossible to see where they may be making contact. It would help to know which wire(s) could be causing the problem. It would have to be a "hot" wire, correct? Which of the wires back there are capable of doing this? The engine doesn't have power trim and tilt, so there's no power going back there for that. Like I said, the view back there is pretty bad, so I'm just trying to narrow down the possibilities.