20hp rough idle

[chriscamp612]

I have a 1990 20hp Johnson 2 stroke model J20EESB. Starts right up, idols rough spits and dies unless i raise idol on controls. runs good but slow down then put in neutral it will spit and die. I have changed spark plugs and wires. Cleaned filter screen at the fuel pump and replaced all fuel line and the fuel tank. if you run this engine wide open the overheat horn comes on but not loud just a little. Got any ideas?

 

[tashasdaddy]

Re: 20hp rough idle

you either have a dirty carb or out of adjustment, you have a slow speed mixture screw on the starboard side of the carb, follow single needle adjustment http://forums.iboats.com/showthread.php?t=299680

 

[mikewoller]

Re: 20hp rough idle

sounds like the low speed adjustment need some tuning.

 

[Mas]

Re: 20hp rough idle

if you run this engine wide open the overheat horn comes on but not loud just a little. Got any ideas?

How is the motor pumping water? When was the last time the impeller was replaced?...if not in the last three years, replace it! How about the thermostat?

MAS