You adjust idle with idle timing
== Is this engine the plastic cowling with idle knob and choke knob on the front pull it to choke and turn to raise idle? = Read more: http://www.justanswer.com/questions/1dpbt-25-hp-mercury-outboard-water#ixzz0HH1RenQM&B
outboard motor will start and idle, but dies out under load
The idle is not adjustible. You may need to clean the throttle plate to improve the idle.
If your engine has a carburettor turn the idle adjust screw so the idle is at the proper speed. If your engine has fuel injection the ECM controls the idle.
Right at the top of the engine you will find the carb immediatley to the right on the carb you will see a flat head screw this will adjust your idle , helps to have a second person on this.
To adjust the idle on a 1984 Mercury Capri, first ensure the engine is at operating temperature. Locate the idle adjustment screw on the throttle body; this is typically a flathead screw. Turn the screw clockwise to increase the idle speed or counterclockwise to decrease it, aiming for the recommended RPM specified in the owner's manual. Finally, check the idle speed using a tachometer and make any necessary fine adjustments.
To find the idle adjust on a caterpillar 3406 engine refer to the owners manual. If this doesn't help, contact the manufacturer.
You adjust the run and idle speed with the governor wire...loosen the nut and adjust it.
carburetor or spark plugs
How do you adjust the idle speed on a citroen berlingo 1.9d (basic diesel engine)
You can't - it's all controlled from the PCM.