Lycoming IO-390-D Series Maintenance Manual page 284

CAUTION
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.
Condition
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)
Damaged, pitted, nicked, dented, loose, crimped
or kinked fuel line or fuel line with sharp bends
greater than that shown in Figure 3
No clamps installed on fuel line that had been in
service
Loose clamps
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.)
Problem with fuel injector clamp installation
caused by obstructive baffling
* Refer to the "Fuel Line Replacement" procedure in this chapter.
73-10
Page 258
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.
Corrective Action for Fuel Lines
IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
Table 1
Corrective Action
Do NOT repair any fuel line that leaks or is
cracked, brittle, worn, or chafed.
Replace the fuel line with a new fuel line.*
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.*
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.*
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.*
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.
Install the fuel injector clamps to enable
clearance.
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March 2020