1996 johnson 150hp is "coughing"

[cpoynter84]

I just rebuilt the carbs and put them back on and now the engine is sputtering or "coughing" at idle speeds and in neutral idle. Any ideas? I have also noticed a hesitation at throttle up. It runs fine and speeds.

 

[spingley]

Re: 1996 johnson 150hp is "coughing"

I have an 86 90HP and rebuilt both carbs on it last summer, it did basically the same thing as you describe, I was at a loss for awhile until I checked the throttle plates and seen that they were not opened the same amount, I did a basic link and sync and it idled great after that. I am guessing that in the process of removing/installing the carbs that things on all that linkage got changed.

 

[cpoynter84]

Re: 1996 johnson 150hp is "coughing"

this is going to sound bad but how do you adjust the linkage?

 

[jonesg]

Re: 1996 johnson 150hp is "coughing"

Loosen the lockscrew, hold plates closed and tighten it.
Before doing that make sure they all close at idle and all sit 90 degs level at WOT.
If they do, its good and doesn't need touching.
I'd get the factory service book too, not seloc or clymer versions.

Cough or sneeze is a lean condition, air leak possibly.
Re-check the carb installations, a seal out of place can cause this.
A loose bowl, link and sync out of spec. All possible sources.

When its sneezing at idle, place two fingers in each carb in turns to choke it individually, often you can trace the leaking carb when it starts to idle smoother as you choke it.