TM 5-3810-300-24&P-3
1.0
TROUBLE SHOOTING
______________________________________ SUGGESTED REMEDY ______________________________________
1. Check for carbon deposits, a bent valve guide,
7. Black carbon deposits extending from the valve
defective spring or antifreeze (glycol) in the
seats to the guides indicates cold operation due to light
lubricating oil. Replace a bent guide. Clean-up and
loads or to the use of too light a fuel. Rusty brown valve
reface the valve. Replace the valve if necessary.
heads with carbon deposits forming narrow collars
2. Check for excessive valve-to-guide clearance, bent
near the guides indicate hot operation due to overloads,
valve guide or carbon deposits. Replace a bent or worn
inadequate cooling or improper timing which results in
guide. Clean the carbon from the valve. Reface or
carbonization of the lubricating oil. Clean-up the valves,
replace the valve, if necessary.
guides and inserts. Reface the valves and inserts or
replace them if they are warped, pitted or scored.
3. Check the operating conditions of the engine for
overload, inadequate cooling or improper timing. Reface
8. Check for a worn valve guide or excessive exhaust
the valve and insert. Replace the valve if it is warped or
back pressure. Replace a worn guide. Check the valve
too badly pitted. Use a harder-face valve if the operating
seat for improper seating. Reface the valve and insert
conditions warrant.
or, if necessary, replace.
4. Check for contact between the valve head and the
9. Check for a bent valve stem or guide, metal chips or
piston as a result of incorrect valve clearance, an
dirt, or for lack of lubrication. Clean up the valve stem
improperly positioned exhaust valve bridge (four valve
with crocus cloth wet with fuel oil or replace the valve.
head) or a defective spring. Check the valve guide,
Replace the guide. When installing a valve, use care in
insert, cylinder head and piston for damage. Replace
depressing the spring so that the spring cap DOES NOT
damaged parts.
scrape the valve stem.
5. Check for excessive valve-to-guide clearance, a
10. Check for a gear train failure or for improper gear
defective valve spring or etching of the valve stem at the
train timing.
weld. Improper valve clearance is also a cause of this
type of failure. Check the guide, insert, cylinder head
11. Check the operation of the engine for excessive
and piston for damage. Replace damaged parts.
idling and resultant low engine exhaust back pressure.
Install valve guide oil seals.
6. Replace a worn valve guide. Check and replace the
valve, if necessary.
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