Valve Sticking - Lycoming YO-233-B2A Maintenance Manual

YO-233-B2A Engine Maintenance Manual
TEO-540-A1A Engine Maintenance Manual
Maintenance after flight...
Examine the external condition of the engine,
all accessories, compressor, external fuel and
oil cooling air baffles, oil hoses, and all other
components for corrosion or scoring. Identify
any possible damage caused by the high speed
impact of solid particles and corrosive effects
caused by the chemical composition of volcanic
ash.
Drain all other fuel/fluids from the engine and
replace with clean fluids. Replace the
disposable fuel filter. Remove and clean the
fuel inlet screen.
Examine seals for damage and leaks. Replace
damaged or leaky seals.
Clean the engine with high pressure air spray.
Be sure to clean the cooling fins on the
cylinder.
In volcanic ash fall-out or high sand or dust
areas, after the engine cools install inlet and
exhaust covers to prevent airborne volcanic ash
from entry into the static engine.
NOTICE: Additional measures may be necessary in specific operating conditions.
H. Valve Sticking
The primary causes of intake or exhaust valve sticking are:
(1)
(a) Accumulated contaminants in the oil and oil filter can collect on valve stems to prevent
valve movement and cause intermittent engine hesitation or "miss." If the contamination
deposits are not removed, the valve becomes stuck and causes engine damage. In hot
ambient temperatures, lead salts from leaded (aviation) fuel can cause oil contamination
but the lead salts are removed when the oil and the oil filter are replaced.
(b) Other conditions that can increase oil contamination include:
— High ambient temperature
— Slow flight with reduced cooling
— High lead content in fuel
— Oil and filter changes not done as frequently as necessary. Refer to the section
— Induction system not sealed - unfiltered air enters engine
© 2021 Avco Corporation. All Rights Reserved
February 2021
Table 2 (Cont.)
Action to Take in Volcanic Ash Conditions
"Oil Change and Oil Filter Replacement Schedule" in Chapter 12-10
Maintenance after 10 hours of operation or the
next flight
Examine the external condition of the engine, all
accessories, compressor, external fuel and oil
cooling air baffles, oil hoses, and all other
components for corrosion or scoring. Identify any
possible damage caused by the high speed impact
of solid particles and corrosive effects caused by
the chemical composition of the volcanic ash. Do
this inspection again as necessary.
Remove and examine the fuel filter to identify
contamination. Replace the fuel filter if
contamination is found.
Monitor oil temperature and pressure for
indications of engine problems.
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