Lycoming IO-390-D Series Maintenance Manual page 24

Cylinder Number Designations
• The propeller is at the front of
the engine.
• When viewed from the top of
the engine, the left side
cylinders are 2-4. Cylinder 2
is at the front of the engine.
Refer to Figure 4.
• When viewed from the top of
the engine, the cylinders on
the right are 1-3. Cylinder 1 is
at the front of the engine.
Refer to Figure 4.
• The firing order of the
cylinders is 1-3-2-4.
Scope of this Manual
This manual supplies instructions (in compliance with Federal Aviation Regulation (FAR 33.4)) for
maintenance of the Lycoming IO-390-D Series engine. These instructions include: required
maintenance (service information) such as: oil changes, oil addition, oil filter replacement/oil
pressure screen cleaning, routine time-interval inspections, routine service, spark plug
replacement/inspection procedures, cylinder inspection, fuel system inspection, scheduled servicing
procedures, airworthiness limitations, fault isolation guidelines and procedures to replace
components and to disassemble and assemble the engine. Refer to the applicable parts catalog to
identify spare parts.
Instructions for Continued Airworthiness
This manual, the IO-390-D Series Engine Overhaul Manual, the latest revision of the Service Table
of Limits - SSP-1776, and service documents applicable to this engine model make up the complete
set of Instructions for Continued Airworthiness (ICAs). The ICAs are prepared by Lycoming
Engines.
Engine Certification
This manual adheres to guidelines set forth by the FAA for certified engines. All inspections,
procedures, and guidelines in this manual must be followed to maintain continued airworthiness.
Compliance Requirements
FOR CORRECT ENGINE MAINTENANCE, COMPLETE THE NECESSARY
MAINTENANCE PROCEDURES IN THIS MANUAL AND APPLICABLE
SERVICE DOCUMENTS. LYCOMING ENGINES' SERVICE DOCUMENTS
WRITTEN AT A LATER DATE SUPERSEDE PROCEDURES IN THIS
MANUAL UNLESS OTHERWISE SPECIFIED.
PROCEDURES IN THIS MANUAL MUST BE DONE BY QUALIFIED
PERSONNEL WITH THE REQUISITE CERTIFICATIONS.
Before you do maintenance on the IO-390-D series engine, read this manual in its entirety. Obey all
procedures and inspections in this manual.
Introduction
Page xxii
IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
Top View of Engine – Cylinder Number Designations
© 2020 Avco Corporation. All Rights Reserved
Figure 4
March 2020