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SECTION 10
INSPECTION AND RECONDITIONING
Leakage: A poor grind on face or seat of valve will allow leakage
resulting in a burned valve on one side only.
Coking: Coking is normal on intake valves and is not harmful, И
the seat is good, the valve could be reused atter cleaning.
Excessive Combustion Temperatures: The white deposits seen
here indicate very high combustion temperatures, usually due to a
lean fue! mixture.
Gum: Gum deposits usually result from using stale gasoline. This
condition is often noted in applications where fuel is not drained
out of tank during the off season. Gum is a prevalent cause of
valve sticking. The cure is to ream the valve guides and clean or
replace the valves, depending on their condition.
Stem Corrosion: Moisture in fuel or from condensation are the
most common causes of valve stem corrosion. Condensation oc-
curs from improper preservation during storage and when engine
is repeatedly stopped before it has a chance to reach normal oper-
ating temperatures. Replace corroded valves.
Overheating: An exhaust valve subject to overheating will have a
dark discoloration in the area above the valve guide. Wom guides
and faulty valve springs may cause this condition, Also check for
clogged air intake, blocked fins, and lean fuel mixture when this
condition is noted.
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