1984 Johnson 115 run on after shut off

[parrisw]

This year sometimes after turning the key off the engine runs on for maybe 5-10s, sometimes it does it sometimes it doesn't?? Any reason for this? It never did it last year, and everything is unchanged.

 

[boobie]

Re: 1984 Johnson 115 run on after shut off

Make sure your idle speed is correct and do a GOOD Decarb on it.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Ok, what's the idle speed spec? I think its below 1000 now.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Just had a thought. I did change the plugs this year. It actually seemed to coincide with that. Before it had NGK which apparently aren't the exact right plugs for the motor, so I put in some Champions, I think QL77JC4's. I didn't notice any difference in running or starting ability. Is it possible that the Champions are a hotter plug? I'm thinking of trying the NGK's again and see if the problem goes away.

 

[emdsapmgr]

Re: 1984 Johnson 115 run on after shut off

Possible one of the power packs is going bad. That engine has dual power packs. I've see one pack fail, such that it does not respond to the kill switch wire from the key switch. That engine will run on with only one pack still firing the two cyls. You may notice a difference in the sound of the engine if you toggle the key switch back and forth from off to on, when the engine is running on. That sound change may be the difference between running on two or 4 cyls.

 

[fmalott]

Re: 1984 Johnson 115 run on after shut off

The two most common reasons for run on, is high idle rpm, and an immediate shut down of the engine after a hard run.
Let the engine idle for a couple of minutes after coming off plane, to burn off excess fuel from slowing down, and allow the engine to cool. and do what boobie said decarb you might have a alot of carbon build up

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Possible one of the power packs is going bad. That engine has dual power packs. I've see one pack fail, such that it does not respond to the kill switch wire from the key switch. That engine will run on with only one pack still firing the two cyls. You may notice a difference in the sound of the engine if you toggle the key switch back and forth from off to on, when the engine is running on. That sound change may be the difference between running on two or 4 cyls.

Yes that's what it sounds like. Thanks I'll look into it. Anyway to tell which power pack is bad?

The two most common reasons for run on, is high idle rpm, and an immediate shut down of the engine after a hard run.
Let the engine idle for a couple of minutes after coming off plane, to burn off excess fuel from slowing down, and allow the engine to cool. and do what boobie said decarb you might have a alot of carbon build up

I usually do let it idle for a minute, last year even after a hard run pulling a 3man tube, it never did it.

 

[emdsapmgr]

Re: 1984 Johnson 115 run on after shut off

Use an inductive timing light to check for spark when the engine is running on. The spark plug leads to one head may be firing, the other not.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Can anyone help me with a wiring diagram for this engine 1984 Johnson 115 or tell me which wire is the kill wire at the power packs? Does the key switch just ground these wires? I'd like to get this problem fixed this year. I ran it in the drive way for only maybe 2 minutes at most, and it ran on after that, so I don't think its a carbon issue.

 

[emdsapmgr]

Re: 1984 Johnson 115 run on after shut off

Did you look at the thread at the top of this website about wiring diagrams?

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Did you look at the thread at the top of this website about wiring diagrams?

No didn't see it.

 

[66evinrude]

Re: 1984 Johnson 115 run on after shut off

my boat did same thing it was key switch one way i found out it was key switch is unhooked all wires off key switch there are two wire that you touch together to shut engine off hope this help?

 

[wired247]

Re: 1984 Johnson 115 run on after shut off

I had a bad power pack do the same thing. 2 day old CDI.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Thanks guys for the tips. I'll check the key switch, if that don't do it, I'll go on to the power pack's.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Well I found a problem, not sure if it's the whole story yet. The ign switch was bad for sure. The two M terminals when the key is off should have continuity, and they did, however with the key on they shouldn't have continuity but they did???? Wierd, I don't know how the engine even ran like that. So I picked up a new switch today and with the key on there was no continuity. Now the odd time when I started it, it did it yesterday it sounded the same as when I was trying to shut it off sounded like only running on 1 or 2 cylinders for a few seconds then it straightened out, today I ran it after putting the new switch in and it never did that again, and it seemed to shut off much better, but after it got hot it did run on slightly, but every time I run on the muffs it runs too hot, so I'll wait till I get it to the lake to make the final call on it. Right now idling on muffs it seems to be just below 1000rpm.

Thanks to all that helped.

 

[66evinrude]

Re: 1984 Johnson 115 run on after shut off

Glad you took my advice. Let us know how she preforms on the lake. Might take my boat out tonight

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Glad you took my advice. Let us know how she preforms on the lake. Might take my boat out tonight

Yes, thanks very much.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Well had it at the lake today. It does seem better but not 100%, if I let it idle for a minute it shut off fine.

 

[parrisw]

Re: 1984 Johnson 115 run on after shut off

Ok I know this is an old thread, but I figured I owe it to you guys to update. This year, crappy weather so far so only had it out twice, the first time, it still ran on every time. GRRRRR, so the other day, I decided to try NGK plugs again, and I was certain that this problem arose when I put Champions in it, so, I installed some new NGK plugs and the other day, every time I shut it off it was fine, it shut down instantly!!! Very happy about that!!! I looked through the plug holes and wasn't much carbon at all, this engine gets run hard when I use it, always pulling a 3 man tube, and when not doing that I'm trolling with my kicker. Also for good measure I dumped a can of seafoam in the tank, as well as sprayed some in the cylinders, I don't think that fixed it since I don't think it would act that fast.

Anyway I'm pretty happy that its fixed, Its really annoying when your idling up to a beach and go to shut it off when trying to beach the boat and the stupid motor runs on, because I hate lifting the motor out of the water with it still running.