IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved
73-10
March 2020
Page 257
IO-390-D Series Engine Maintenance Manual
B.
Examine each fuel line for damage, leaks, dents,
pits, nicks, kinks, stains (from fuel leaks), cracks,
brittleness, nearby heat sources, chafing,
looseness, crimped, kinked, or sharp bends. Refer
to Figure 3 which shows the minimum acceptable
dimensions for a bend in the fuel line. Replace (do
not try to repair) a worn, damaged, chafed, brittle,
crimped, sharply bent, kinked, or loose fuel line.
(A loose fuel line could have been subjected to
vibrational forces and be weakened. Cracks can
develop at kinks in fuel lines.)
Figure 3
Minimum Acceptable Dimension
for a Bend in a Fuel Line
CAUTION
TO SUPPORT FUEL SYSTEM PERFORMANCE, ALL WORN,
DAMAGED, CHAFED, BRITTLE, KINKED, OR LOOSE FUEL LINES
MUST BE REPLACED - NOT REPAIRED.
MAKE SURE EACH FUEL LINE IS INSTALLED WITH SERVICEABLE
CUSHIONED CLAMPS TO KEEP THE FUEL LINES SECURELY IN
PLACE TO PREVENT FUEL LINE DAMAGE DUE TO VIBRATION
AND FRICTION AGAINST OTHER PARTS OF THE ENGINE.
VIBRATION, RUBBING, AND/OR KINKS IN THE FUEL LINES CAN
CAUSE CRACKS IN THE FUEL LINES. AS A RESULT, THE FUEL
LINES CAN EVENTUALLY BREAK, LEAK FUEL ON THE ENGINE,
AND CAUSE A FIRE OR ENGINE STOPPAGE.
C.
Make sure all fuel lines are held in place securely using serviceable cushioned clamps to
prevent fuel line movement due to vibration.
(1)
Make sure each clamp securely supports the fuel line to prevent fuel line movement due
to vibration, friction, or motion frequencies.
Do NOT use plastic tie straps as clamps
.
(2)
Examine the cushion on clamps for deterioration. If cushions are deteriorated or missing,
replace the clamp with a new clamp with the cushion intact.
(3)
On engines that use metal clamps with no cushion, install a fuel line sleeve at each clamp
location.
(4)
If a fuel line had been in service and clamps were not installed, replace the fuel line
with a new fuel line (as a precaution since vibration can cause cracks in the fuel
lines.)
(5)
Make sure the clamps are securely attached. If the clamps are loose, replace the fuel line.
CAUTION
REPLACE ANY FUEL LINE THAT IS CRACKED, DENTED, OR
KINKED; CRACKS CAN DEVELOP AT THE SITE OF SHARP
BENDS OR KINKS.
D.
Examine solder joints at the end of fuel lines for cracks. Replace the fuel line if a crack is
found at a solder joint.
WARNING
DO NOT ROUTE FUEL LINES CLOSE TO HEAT SOURCES. HEAT
CAN CAUSE FUEL VAPORIZATION IN THE FUEL LINES OR CAN
DAMAGE THE FUEL LINE AND CAUSE A FUEL LEAK WHICH
COULD LEAD TO ENGINE STOPPAGE.
