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1986 Johnson 140 hesitates or cuts off at running speed

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tomcoates50

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Trolling for 4 hours with no problems. Running 2 miles back to marina at 3500 Rpms in choppy water, engine hesitated as if it were going to stall. More throttle kept it running. Backed off on speed due to conditions. This occurred 5 times on trip back to dock.

In the past, prior to replacing power pack and stater, engine would die at running speed and not restart requiring several tows. Mechanic checked compression - good. New plugs installed prior to trip. Fuel treated with sea foam.

Engine 1986 J140TXCDC V4 VRO
 
I was leaning toward float levels...rough water will cause slugs of fuel to be thrown into throat thru carb vent. Had this problem racing as need slosh tubes installed
 
tomcoates50 said:
Trolling for 4 hours with no problems. Running 2 miles back to marina at 3500 Rpms in choppy water, engine hesitated as if it were going to stall. More throttle kept it running. Backed off on speed due to conditions. This occurred 5 times on trip back to dock.

In the past, prior to replacing power pack and stater, engine would die at running speed and not restart requiring several tows. Mechanic checked compression - good. New plugs installed prior to trip. Fuel treated with sea foam.

Engine 1986 J140TXCDC V4 VRO
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I discovered a compromised fuel line to one of the 4 carbs, replaced it and have not had a problem with engine hesitation since.

CONTINUED ISSUE: Engine stalls at idle speed when coming into dock.

Idle specs call for idle set at 600-700. Service mechanic has it set at 900. engine idles fine at the dock. I have cleaned carbs, which didn't seem dirty to start. After returning to port, approaching dock and bringing engine down to idle speed, engine will stall before I complete docking.

I found a very informative video on YouTube for this exact problem. However, that video was for a 1986 J140TXCD engine. I don't know if a "letter" makes a difference, but my engine is a 1986 J140TXCDC. The video showed an adjustment on each carb with a #20 Torx screw. My carbs don't have this Torx screw.

How do I maintain engine idle without stalling?
 
Perhaps there is an issue with the crankcase compression.------Not the same as compression in the cylinder.------Your mechanic will know how to inspect that on these early looper style engines.
 
racerone said:
Perhaps there is an issue with the crankcase compression.------Not the same as compression in the cylinder.------Your mechanic will know how to inspect that on these early looper style engines.
Click to expand...


Thank you. I will call mechanic on Monday. Hopefully he can get me in quickly. Don't want to put Grandkids on the boat when I'm not confident in the engine.
 
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