1985 Johnson 140 cutout

socalgsx

Cadet
Joined
Aug 10, 2005
Messages
10
I started having a problem when I went off shore last time. I could troll all day but when I went to take off it would cutout like it died, I would put it in neutral and it would drop down to idle and run fine. I found a loose fuel line and corrected that then it ran better. But it would still cut out every once in a while during my transit back that day(I was 40 miles out). The rest of the day it "cutout" a few more times. Once we were done fishing and headed home about 12 miles it ran pristine. Didnt cutout at all.

I got home changed plugs L77JC4, fuel filter, fuel/water seperator filter, and seafoamed the engine. My compression on all four is 130. I went out this weekend and I was about 20 miles out and it started to cutout agian so I promptley turned around and went back to the bay and fished their for a few hours. when I started the engine this time it ran fine untill I went to throttle it up and it cutout but it was running but then cutout and run and the engine was moving back and forth like jerking ie run-stop-run-stop-run. I tried pumping the bulb it was stiff and made no change. then it died totally. I took the cowel off adn check lines everything was tight and good. Then I got it back running after three hours I turned the red switch at the bottom of the carbs and if finally fire up and I got home. When I flushed the engine at home it started the jerking thing agian and has not started since then.

I checked the spark when it was jerking and it is firing. I checked the fuel pump to see if it was pumping and gas came out when I turned over the engine. I am totally stumped and I really dont want to pay someone $80 and hour to figure out something that I can figure out myself.
 
Last edited:

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1985 Johnson 140 cutout

Your explanation is both detailed and indicates you know your engine well. First guess is that it is an electrical issue. These tend to show up when the engine is well warmed up. Take an inductive timing light with you the next time you go out. When the engine starts to miss, take the cowl off and check each plug wire for a strong, constant spark while running. Look for intermittent, or weak flashes. If you don't see anything on the timing light, while it is "jerking," it is probably fuel related.
 
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