Lubrication System; Oil Grades And Limitations; Oil Sump Capacity; Oil Suction And Oil Pressure Screens - Lycoming O-290 Operator's Manual

LYCOMING OPERATOR'S MANUAL
O-235 AND O-290 SERIES
(3) Set throttle stop screw so that the engine idles at the airframe manufacturer's recommended idling
RPM. If the RPM changes appreciably after making idle mixture adjustment during the
succeeding steps, readjust the idle speed.
(4) When the idling speed has been stabilized, move the cockpit mixture control lever with smooth,
steady pull toward the "Idle Cut-Off" position and observe the tachometer for any change during
the leaning process. Caution must be exercised to return the mixture control to the "Full Rich"
position before the RPM can drop to a point where the engine cuts out. An increase of more than
50 RPM while "leaning" out indicates an excessively rich idle mixture. An immediate decrease in
RPM (if not preceded by a momentary increase) indicates the idle mixture is too lean.
If the above indicates that the idle adjustment is too rich or too lean, turn the idle mixture
adjustment in the direction required for correction, and check this new position by repeating the
above procedure. Make additional adjustments as necessary until a check results in a momentary
pick-up of approximately 50 RPM. Each time the adjustment is changed, the engine should be run
up to 2000 RPM to clear the engine before proceeding with the RPM check. Make the final
adjustment of the idle speed adjustment to obtain the desired idling RPM with closed throttle. The
above method aims at a setting that will obtain maximum RPM with minimum manifold pressure.
In case the setting does not remain stable, check the idle linkage; any looseness in this linkage
would cause erratic idling. In all cases, allowance should be made for the effect of weather
conditions and field altitude upon idling adjustment.

3. LUBRICATION SYSTEM.

a. Oil Grades and Limitations – Service the engine with grade recommended in Flight Chart, Section 3,
page 3-6.
b. Oil Sump Capacity –
O-235 Series........................................................................................................................6 U. S. Quarts
O-290-D and –D2 Series .....................................................................................................8 U. S. Quarts
Minimum Safe Quantity in Sump .......................................................................................2 U. S. Quarts
c. Oil Suction and Oil Pressure Screens – For engines without a full flow oil filter, change oil and
inspect and clean screens every 25 hours.
On installations employing full flow oil filters, step c. is not practical at this time, but should
be observed at the 100-hour inspection.
d. Oil Relief Valve – Subject engines are equipped with either an adjustable or a non-adjustable oil relief
valve located in the right crankcase half to the rear of no. 3 cylinder pad. The adjustable valve will
maintain the oil pressure within specified limits by screwing the adjusting screw inward to increase
pressure and outward to decrease pressure. The non-adjustable valve can control pressure by the
addition of a maximum of nine STD-425 washers under the cap to increase pressure of a spacer (P/N
73629 or 73630) under the cap to decrease pressure.
MAINTENANCE PROCEDURES
NOTE
SECTION 5
5-5