Spark Plug Fouling - Lycoming TEO-540-C1A Maintenance Manual

TEO-540-C1A Engine Maintenance Manual
TEO-540-C1A Engine Maintenance Manual
D. Measure the spark plug gap (identified by the spark plug manufacturer) to make sure it is at
the correct tolerance per the spark plug manufacturer's instruction. Reset the spark plug gap
if it is not correct. Refer to the "Spark Plug Gap Setting" procedure in this chapter.

6. Spark Plug Fouling

Lead deposits can collect on the spark plug electrodes when the engine operates at lower-
A.
than-specified temperatures with fuel-rich mixtures (fuel-rich mixtures do not enable
vaporization of lead in aviation gas). These deposits can cause misfiring.
Recommendations to prevent spark plug fouling:
B.
• If the engine is approved for use with unleaded fuel per Appendix A in the TEO-540-C1A
Engine Installation and Operation Manual, use unleaded fuel after purging the fuel
system.
• Rotate top and bottom spark plugs every 100 operating hours or annually – refer to the
"Spark Plug Rotation" procedure in this chapter.
• Operate the engine between 1000 and 1200 rpm after engine start and during warm-up.
(At these speeds the spark plug core temperatures are sufficiently hot to activate the lead
scavenging agents to prevent lead deposits on the spark plugs and exhaust valve stems.)
• Operate the engine at the specified operating temperature to prevent low temperature
operation.
• Use oil cooler baffles to keep the oil temperature from decreasing during winter flight.
• Avoid rapid power reduction in flight to prevent sudden engine cooling.
• Do not stop the engine immediately after landing to prevent rapid engine cooling.
• Before engine shutdown, operate the engine between 1000 and 1200 rpm until operating
temperatures are stable and EGTs drop below 1100°F (593°C). Then increase engine
speed to 1800 rpm for 15 to 20 seconds. Then decrease engine speed to between 1000 and
1200 rpm before engine shutdown.
7. Spark Plug Port Seal Inspection
NOTICE: This inspection is usually done to complete the check of the Heli-coil
in the cylinder head.
A. Disconnect the battery and remove the ignitions leads from all spark plugs.
B. Apply a soap solution to the spark plug seating area of the cylinder head.
C. Turn the propeller/crankshaft by hand to move the piston, in the cylinder to be inspected, to
top dead center of the compression stroke.
D. Look for bubbles around the spark plug. If bubbles are seen, replace the Heli-coils
all loose or damaged spark plug Heli-coil
Chapter 72-30.
E. Examine the spark plugs (if not already done). Refer to the section "Spark Plug Inspection"
procedure in this chapter.
F. Examine the surface of the cylinder (covered with soap) for cracks. Refer to the "Visual
Cylinder Inspection Procedure" in Chapter 72-30.
© 2018 Avco Corporation. All Rights Reserved
November 2018
®
inserts with oversize inserts per instructions in
®
spark plug insert
®
. Replace
74-20
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