1982 Mercury 18 hp Runs Rough

JDusza

Ensign
Joined
Apr 21, 2009
Messages
934
Thank you for taking my question.
I have an 18 that runs excessively rough, only sometimes clearing up at full throttle. When it clears up, of course it runs like a beast!
It chokes up at idle and sometimes remains choked at full throttle and sometimes clears up at full throttle.
I have been trying to adjust with the idle adjustment needle and am running much smoother at lower speeds.
I see in a parts list four (4) main jets are available for this engine.
Can anyone recommend how to adjust the carb correctly or recommend a smaller main jet?
Thank you,
Jim
 

Wingedwheel

Lieutenant Junior Grade
Joined
Jun 16, 2009
Messages
1,071
Re: 1982 Mercury 18 hp Runs Rough

Are you just adjusting or have you cleaned the carb also?
 

JDusza

Ensign
Joined
Apr 21, 2009
Messages
934
Re: 1982 Mercury 18 hp Runs Rough

I haven't pulled the carb off the manifold yet. The engine is running and we are enjoying it.
I have put Techron through the fuel system in an attempt to run it clean and performance has improved. I just can't quite get the lean out it needs at high end.
 

Wingedwheel

Lieutenant Junior Grade
Joined
Jun 16, 2009
Messages
1,071
Re: 1982 Mercury 18 hp Runs Rough

No matter what you run through it, it still won't get it completely clean. A kit would probably help out more than you think.
 
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