IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved
72-05
March 2020
Page 107
IO-390-D Series Engine Maintenance Manual
72-05- ENGINE DISASSEMBLY
Engine disassembly begins after the oil has been drained from the engine per instructions in Chapter
12-10, and the engine is removed from the airframe (per instructions in this manual and the
applicable Airframe Maintenance Manual).
Follow the procedures for engine disassembly for the IO-390-D engine in the sequence identified in
Table 1.
Table 1
Sequence of IO-390-D Series Engine Disassembly Procedures
Step
Reference
Step
Reference
Step 1
“Spark Plug Removal” procedure in
Chapter 74-20
Step 3
“EIS Removal” or “Magneto Removal”
procedure in Chapter 74-30
Figure 3
EIS/Magnetos
Remove the
spark plugs
(Figure 1).
Remove the
two
Lycoming
Electronic
Ignition
Modules or
magnetos
(Figure 3).
Figure 1
Spark Plugs
Step 2
Remove the
ignition
harness and
ignition
leads
(Figure 2).
“Ignition Harness Removal” procedure
in Chapter 74-20
Step 4
Remove the
oil level
gage
assembly
and oil level
gage tube
(Figure 4).
“Oil Level Gage Tube and Assembly
Removal” procedure in Chapter 72-50
Figure 4
Oil Level Gage Tube
Figure 2
Ignition Harness
NOTICE:
In this chapter the term “magneto” can refer to either the Lycoming Electronic Ignition
System (EIS) or optional, traditional magnetos, depending on the type of system
installed on the engine.
