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