400-Hour Inspection; Non-Scheduled Inspections - Lycoming O-290 Operator's Manual

SECTION 4
PERIODIC INSPECTIONS
f. Priming Nozzles – Disconnect primer nozzles from engine and check for equal flow.
g. Valve Rockers (O-235 and O-290-D) – Check clearance. See Page 5-9, Paragraph (11) for valve
rocker clearance.
h. Carburetor – Check throttle body attaching screws for tightness. The correct torque for these screws
is 40 to 50 in.-lbs.
i. Lubrication System – Drain and renew lubrication oil. Replace oil filter.
5. 400-HOUR INSPECTION. In addition to the items listed for daily pre-flight, 50-hour and 100-hour
inspections, the following maintenance check should be made after every 400 hours of operation.
Valve Inspection – Remove rocker box covers and check for freedom of valve rockers when valves are
closed. Look for evidence of abnormal wear or broken parts in the area of the valve tips, valve keeper,
springs and spring seat. If any indications are found, the cylinder and all of its components should be
removed (including the piston and connecting rod assembly) and inspected for further damage. Replace any
parts that do not conform with limits shown in the latest revision of Special Service Publication No. SSP-
1776.
6. NON-SCHEDULED INSPECTIONS. Occasionally, service bulletins or service instructions are issued by
Lycoming that require inspection procedures that are not listed in this manual. Such publications, usually
are limited to specified engine models and become obsolete after corrective modification has been
accomplished. All such publications are available from Lycoming distributors, or from the factory by
subscription. Consult latest revision of Service Letter No. L114 for subscription information. Maintenance
facilities should have an up-to-date file of these publications available at all times.
4-4
LYCOMING OPERATOR'S MANUAL
O-235 AND O-290 SERIES