IO-390-D Series Engine Maintenance Manual
73-10
© 2020 Avco Corporation. All Rights Reserved
Page 258
March 2020
IO-390-D Series Engine Maintenance Manual
CAUTION
DO NOT RETURN THE ENGINE TO SERVICE UNLESS THE ENGINE
IS OPERATING CORRECTLY AND DOES NOT HAVE ANY LEAKS.
THERE MUST NOT BE ANY FUEL LEAKS. A FUEL LEAK CAN
CAUSE A FIRE.
E.
Make sure no fuel lines touch the engine or aircraft baffle hardware. There must be a
minimum clearance of 3/16 in. (4.76 mm) between a fuel line and any engine or aircraft
surface.
F.
After the inspection, refer to Table 1 for any corrective action if necessary.
Table 1
Corrective Action for Fuel Lines
Condition
Corrective Action
Leaky, cracked, brittle, worn, chafed, fuel line
Bent (non-kinked) stainless steel fuel lines that
have an inside radius less than 5/8 in. (15.88
mm)
Do NOT repair any fuel line that leaks or is
cracked, brittle, worn, or chafed.
Replace the fuel line with a new fuel line.*
Damaged, pitted, nicked, dented, loose, crimped
or kinked fuel line or fuel line with sharp bends
greater than that shown in Figure 3
Do NOT re-use any fuel line that is damaged,
dented, pitted, crimped, or kinked. Dents can
cause cracks to form.
Replace the fuel line with a new fuel line.*
No clamps installed on fuel line that had been in
service
Replace the fuel line with a new fuel line and
install serviceable cushioned clamps on the fuel
line to securely hold the fuel line in place and
prevent fuel line movement from vibration.*
Loose clamps
Replace the fuel line with a new fuel line and
install serviceable cushioned clamps on the fuel
line to securely hold the fuel line in place and
prevent fuel line movement from vibration.*
Deteriorated cushion on clamp, missing
cushion, or cushion does not completely cover
the fuel line diameter. (On engines that used
metal clamps with no cushion, use the P/N LW-
12598 fuel line sleeve at each of those clamping
locations. The fuel line sleeve is not used with
the cushioned clamps.)
Examine fuel lines in areas adjacent to the
clamp. Replace any fuel line that has any
conditions identified above.*
Replace the clamp with a new serviceable
cushioned clamp.
Problem with fuel injector clamp installation
caused by obstructive baffling
Install the fuel injector clamps to enable
clearance.
* Refer to the “Fuel Line Replacement” procedure in this chapter.
