Idle Adjustment Procedures

for

Lycoming Fuel Injected Engines

Contributed by Larry Olson, Express Aircraft Co.

  1. Idle mixture adjustment is accomplished by rotating the idle mixture wheel located on the fuel injection throttle body. Note the idle mixture adjustment is very sensitive and you should not move the wheel more than one notch at a time.
  2. Idle mixture should only be checked and adjusted when the engine is at operating temperature.
  3. To check the mixture setting set the throttle at idle setting (800 RPM). Slowly pull the mixture control out to the fuel cutoff position. You should see a slight rise in engine RPM just prior to the engine stopping. If you do not get a rise the mixture is set to lean. If you get a rise of more that 50-RPM the mixture is too rich.
  4. Adjust the mixture wheel the appropriate direction and repeat the check.
    5.

  5. [FrontPage Image Map Component]

  6. Any air leak in the induction system will be most evident during idle operations so make sure the seals in the induction tubes are installed correctly.