T R O U B L E S H O O T I N G
TM 5-3805-258-24-1
T E S T I N G
A N D
A D J U S T I NG
Cause
Loose Bolt or Nut Holding Pulley or
Damper
Pulley or Damper Has A Defect
Fan Blade Not in Balance
Engine Supports Are Loose, Worn,
or Have a Defect
Misfiring or Running Rough
7. TOO MUCH VIBRATION
Correction
Tighten bolt or nut.
Install a new pulley or damper.
Loosen or remove fan belts and operate engine for a short time at the
rpm that the vibration was present. If vibration is not still present,
make a replacement of the fan assembly.
Tighten all mounting bolts. Install new components if necessary.
Make Reference to Item 3.
8. LOUD
Cause
Bad Quality Fuel
Defect in Fuel Injection Valve(s) or
Fuel Injection Pump(s)
Wrong Fuel Injection Timing
COMBUSTION NOISE (KNOCK)
Correction
Remove the fuel from the fuel tank. Install a new fuel filter element.
Put a good grade of clean fuel in the fuel tank.
Run engine at rpm that gives maximum combustion noise. Then
loosen a fuel line nut on the injection pump for each cylinder, one at a
time. Find the cylinder where loosening the fuel line nut stops the
combustion noise. Test the injection pump and injection valve for
that cylinder. Install new parts where needed.
Make adjustment to timing.
9. LOUD NOISE (CLICKING) FROM VALVE COMPARTMENT
Cause
Correction
Damage to Valve Spring(s) or Locks
Install new parts where necessary. Locks with defects can cause the
valve to slide into the cylinder. This will cause much damage.
Not Enough Lubrication
Check lubrication in valve compartment. There must be a strong flow
of oil at engine high rpm, but only a small flow of oil at low rpm. Oil
passages must be clean, especially those sending oil to the cylinder
head.
Too Much Valve Clearance
Damage to Valves
Make adjustment, See the Subject VALVE CLEARANCE in Test-
ing and Adjusting.
Make a replacement of the valve(s) and make an adjustment as
necessary.
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