Cough and Sneeze

[Jamarine_73]

I seem to have a common problem that has been written about extensively, but I have a new spin to it.

My 1997 Johnson won't behave at idle. After the engine has been run and warm (operating temperature), it does not want to idle. It coughs and sneezes while out of gear and often dies when put in gear. It runs absolutely fine while running on ear muffs, but it appears that the back pressure from being in the water is enough to generate the symptoms.

When warm, it idles around 600 rpm out of gear, and often drops to 500 in gear. It makes it extremely difficult to manuever at the dock or anchoring in close quarters and just embarrasing when the engine simply dies.

I have read a lot about coughing and sneezing when at warm idle and it appears that the two most common opinions are: (1) the carburetors are dirty and the low speed jets need to be cleaned, or (2) the idle needs to be adjusted.

Question 1 - How can you tell the difference between the two causes and trouble shoot the symptoms?

Question 2 - If the idle does need to be adjusted, how can I tell which carburetor needs to be adjusted and how is it accomplished?

I attached some pictures because I am lucky enough to have 6 carburetors and am unsure how to keep them synchronized. Any insight would be helpful!

Engine
Make - Johnson Ocean Runner
Model - J150NXEUC
Serial - G04280272
Year - 1997

Thanks!

 

[bkeltz]

Re: Cough and Sneeze

I have a '94 200 and I am having the same problem. I did a bit of troubleshooting and found one spark plug not get spark. I think that may be the source of the problem but I'm not sure why it's not getting spark. If anyone else has any ideas, please let me know.

 

[Dhadley]

Re: Cough and Sneeze

With OE pistons the motor won't like to idle at 500 in gear. Bring the in gear idle speed up to 650 or so and the issue may resolve itself. Remember - you set the idle with timing, the carb butterflies must remain completely closed.

 

[Jamarine_73]

Re: Cough and Sneeze

With OE pistons the motor won't like to idle at 500 in gear. Bring the in gear idle speed up to 650 or so and the issue may resolve itself. Remember - you set the idle with timing, the carb butterflies must remain completely closed.

I have good mechanical ability, but lack experience with these type motors. The owner's manual was very vague on setting the idle by basically writing, "turn the idle screw until the engine settles out". Not very scientific. Is there a resource with more information on idle and timing setting? Thanks!

 

[Ozerimar]

Re: Cough and Sneeze

Check your sync and link timing the carb throats must all be closed at idle . the throttle linkage and timing plate must be synchronized in perfect time but im betting it s the crappy corn fuel we are buying today. I got the same engine and the same problem so for a while I tried the marina's non ethanol fuel @ $3.75 a gallon vs. marathon's $2.65 e-10 fuel and bingo no heat soak no stupid cough and sputter at idle. I can run it out now for miles shut it off for an hour restart it and go full throttle Its the E-10 fuel thats the problem it wasnt meant for carbed engines in the first place and looks like they want to mix and give us more than 10% now. go figure.

 

[VI-Doug]

Re: Cough and Sneeze

So where is the idle adjustment on this engine? Mine has similar issues with stalling a lot with the forward/reverse at the dock.

 

[Chris1956]

Re: Cough and Sneeze

Doug, You need to purchase an OEM Service manual. It is not as simple as turning a screw to adjust idle timing.

 

[wilde1j]

Re: Cough and Sneeze

Idle rpm is set in the water, in gear ~ 650 RPM.

 

[VI-Doug]

Re: Cough and Sneeze

Doug, You need to purchase an OEM Service manual. It is not as simple as turning a screw to adjust idle timing.

I know, but no one seems to agree on which is a good manual. I don't really want to drop 70 bucks on an OEM manual, and my internet connection won't let me download 277 megs. I'd buy the Seloc manual but so many people say it's worthless.

 

[wilde1j]

Re: Cough and Sneeze

The third party manuals are NFG in my opinion. Try Ebay. OEM books are often there for < $40.

 

[Sixmark]

Re: Cough and Sneeze

AN OEM manual and exploded parts diagrams, study them , sleep with them under your pillow, it will serve you very well, there are also several good sources here in the FAQ/Top Secret section of the forum.

 

[Ozerimar]

Re: Cough and Sneeze

Do yourself a big favor and spend the money on the "REAL" service manual. The OMC Johnyrude manuals are published just for your specific model outboard. Put it this way I have the seloc/ clymer and they are ok and try to cover alot of engine models you will have to hunt around for the procedures and it may not provide clear illustrations of the procedure or part location you are not familiar with where as the OMC manual it gets to the point right away it is clearly written and idiot proof just make sure you have the skill set along with the correct troubleshooting /testing tools. If you can't afford a new one buy a older manual used manual on ebay.