Ground Check - Lycoming O-320 76 Series Operator's Manual

LYCOMING SERIES OPERATOR'S MANUAL
O-320
Any ground check that requires full throttle operation must be limited to three minutes or less
if the indicated cylinder head temperature exceeds the maximum as stated in this manual
(page 3-9).
a. Head the aircraft into the wind.
b. Leave mixture in "Full Rich".
c. Operate only with the propeller in minimum blade angle setting (where applicable).
d. Warm-up at approximately 1000-1200 RPM. Avoid prolonged idling and do not exceed 2200 RPM on
the ground.
e. Engine is warm enough for take-off when the throttle can be opened without the engine faltering.

6. GROUND CHECK.

a. Warm-up as directed above.
b. Check both oil pressure and oil temperature.
c. Leave mixture in "Full Rich".
d. (Where applicable) Move the propeller control through its complete range to check operation and
return it to the full low pitch position. Full feathering check (twin engine) on the ground is not
recommended but the feathering action can be checked by running the engine between 1000-1500
RPM; then momentarily pulling the propeller control into the feathering position. Do not allow the
RPM to drop more than 500 RPM.
e. A proper magneto check is important. Additional factors, other than the ignition system, affect
magneto drop-off. They are load-power output, propeller pitch and mixture strength. The important
thing is that the engine runs smoothly because magneto drop-off is affected by the variables listed
above. Make the magneto check in accordance with the following procedures.
(1) Controllable Pitch Propeller – With the propeller in minimum pitch angle, set the engine to
produce 50-65% power as indicated by the manifold pressure gauge. Mixture control should be in
the full rich position. At these settings, the ignition system and spark plugs must work harder
because of the greater pressure within the cylinders. Under these conditions ignition problems, if
they exist, will occur. Magneto checks at low power settings will only indicate fuel-air distribution
quality.
Aircraft that are equipped with fixed pitch propellers, or not equipped with manifold
pressure gauge, may check magneto drop-off with engine operating at a maximum of 2000-
2100 RPM.
OPERATING INSTRUCTIONS
NOTE
NOTE
SECTION 3
3-3