my newest outboard problem

cdoliver

Petty Officer 1st Class
Joined
Mar 18, 2008
Messages
211
Well, my 1979 jhonny 115 has been running great. All of the sudden, it starts missing at idle. It seems to be ok at higher rpms. I cleaned the carbs. A few things I've noticed is that 3 of 4 plugs are wet. I'm guessing it's a low spark issue. I pulled the plug wires off and they all have spark. Here is another new issue (and this may be the answer to my question), The engine sometimes doesn't turn off after you turn the key off. I know that has something to do with the powerpack, but I'm not exactly sure what. Thanks again.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: my newest outboard problem

The engine not shutting off has to do with the kill circuit (black wire with a yellow tracer). Could be the key switch, kill switch or related wiring. Or internal of the pack.
 

cdoliver

Petty Officer 1st Class
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Mar 18, 2008
Messages
211
Re: my newest outboard problem

ok, I'll trace that wire. Another question:
Would fouled plugs make it miss at idle? I checked all, and they do have spark. Secondly, In my repair manual it says to check resistance of white and yellow with black wires in two directions, testing the diodes. One of them test correctly with no reading in one direction, and a reading in another. The other pack has no reading in either direction. I also have 2 more packs from a '83 140 that I'm rebuilding. I tested them and neither of them have a reading in either direction. Is it possible that I have 3 bad powerpacks? And would a bad powerpack cause the motor to not turn off and/or miss at idle? thanks dhadley.
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
Messages
51,019
Re: my newest outboard problem

i don't believe a bad pack would cause it not to turn of. they are usually a not start or no fire problem. your floats may be set too high. with the wet plugs. the black/yellow wire is the kill circuit.
 

cdoliver

Petty Officer 1st Class
Joined
Mar 18, 2008
Messages
211
Re: my newest outboard problem

I did the key test in the service manual. This deals with testing resistance on the black w/yellow wire at each pack (while turning the key). Both wires test correctly. It is still coughing and sneezing at idle. The key will not kill the motor immediately. It will die after 5 seconds or so, but I think it dies because it is missing so badly. I still have 3 wet plugs and one dry. The dry plug stays with that cylinder...Carb? If I have to pull those carbs off again I will pull my hair out....Can someone reccomend another test I can do. I have temp disconnected the kill switch to eliminate that part. The key switch is new. Dhadly, what do you mean by the internal of the pack? I dont know what else to try. thank you all again.
 

wildmaninal

Lieutenant Commander
Joined
Jul 14, 2007
Messages
1,897
Re: my newest outboard problem

Dhadly, what do you mean by the internal of the pack? I dont know what else to try.


I believe he means something could be breaking down in the the power pack.

I see you have taken the plug wires and tested those... Have you tested the spark plugs by grounding them to the head? When is the last time you replaced the plugs?
 

cdoliver

Petty Officer 1st Class
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Mar 18, 2008
Messages
211
Re: my newest outboard problem

well that gets me to thinking... the plugs are fairly new. a couple of months old. however, the last time I was out the motor got hot. I have since changed the impeller and that fixed the overheat problem (compression still looks good, whew) But looking at the plugs, they are dark black. They may have fouled. I did ground them against the block and they spark. I'll change them and report back. If that fixes the miss, I only have the turning off with the key problem remaining... for now...
 

wildmaninal

Lieutenant Commander
Joined
Jul 14, 2007
Messages
1,897
Re: my newest outboard problem

This got me thinking of these older cars and trucks that try to keep running after the key is shut off and all they might need is a good tune up.

Before you put those new plugs in you could do a good decarb on the motor then replace the plugs.
 
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