Step 5. Engine Stop - Lycoming IO-390-D Series Installation And Operation Manual

IO-390-D Series Engine Installation and Operation Manual
CAUTION
• On engines with manual control, maintain mixture control in the FULL RICH position for
rated take-off, climb and maximum cruise powers (above approximately 75%). However,
during take-off from a high elevation airport or during climb, roughness or loss of power can
occur from over-richness. In such a case, adjust the mixture control only enough for smooth
operation - not for economy. Monitor instruments for temperature rise. Rough operation due
to over-rich fuel/air mixture is most likely to be encountered at altitudes above 5,000 feet
(1524 meters).
• Always return the mixture to FULL RICH before increasing power settings.
• Operate the engine at maximum power mixture for performance cruise powers and at best
economy mixture for economy cruise power; unless otherwise specified in the POH. Refer to
Appendix A.
NOTICE: During descent, it could be necessary to manually lean fuel-injected engines for
smooth operation.
Fuel Mixture Leaning Options
1. Leaning to EGT (Normally aspirated engines with fuel injectors or carburetors).
A. Maximum Power Cruise (approximately 75% power) - Never lean beyond 150ºF (66°C)
on rich side of peak EGT unless the aircraft operator's manual shows otherwise. Monitor
cylinder head temperatures.
B. Best Economy Cruise (approximately 75% power and below) - Operate at peak EGT.
2. Leaning to Flowmeter.
Lean to applicable fuel-flow tables or lean to indicator marked for correct fuel-flow for each
power setting.
3. Leaning with Manual Mixture (without flowmeter or EGT gage).
A. Maximum Power Cruise (approximately 75% power) - Lean to maximum rpm or
airspeed.
B. Best Economy Cruise (approximately 75% power and below).
(1) Slowly lean the mixture until engine operation becomes rough or a rapid decrease in
RPM or airspeed occurs.
(2) Slowly enrich the mixture until engine operation becomes smooth or most of the
RPM or airspeed is restored.

Step 5. Engine Stop

1. After landing, set the propeller at minimum blade angle.
2. Keep the engine speed between 1000 to 1200 rpm, until the operating temperatures are stable
and EGT (if applicable) is approximately 1100ºF (593ºC).
3. Move the mixture control to IDLE CUT-OFF.
4. After the engine stops, set the ignition switch to the OFF position.
© 2020 Avco Corporation. All Rights Reserved
March 2020
NEVER EXCEED THE MAXIMUM RED LINE CHT LIMIT.
Engine Operation
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