TM 10-3950-206-12
Table 4-2. Troubleshooting Chart - Continued
Malfunction
Probable cause
Corrective action
c. Incorrect type V-belt.
c. Use correct V-belt.
d. Fan V-belt worn or burned.
d. Replace V-belt.
e. Align properly.
f. Fan blades loose on hub
f. Tighten capscrews.
g. Replace defective pulley.
distorted.
h. Fan blade striking V-belt or
h. Adjust blades or replace fan.
radiator.
i. Unbalanced fan blade assembly,
i. Replace fan.
bent or distorted blades, or
blades with uneven pitch.
11. Engine pings or knocks.
a. Improper ignition timing.
b. Low-grade fuel.
b. Drain tank and refill with proper
12. Large amount or carbon on
a. Improper grade of fuel.
a. Drain and refill with proper grade .
spark plugs.
b. Weak spark.
b. Inspect distributor, coil and con-
denser. Replace if necessary
c.
Improper timing.
13. Excessive smoke.
a.
a. Fill only to proper level.
b.
Poor carburetion.
a.
Incorrect timing.
b.
Too lean fuel mixture.
15. Excessive fuel consumption.
a.
Engine idles too fast
b.
Incorrect timing
c.
Distributor points improperly set.
c. Set point opening at 0.020"
d. Defective spark plugs.
e. Clogged air cleaner.
f. Fuel pump diaphragm punctured.
f. Install new pump.
g. Restricted exhaust
g. Remove restrictions (Crimp) or
component.
h. Throttle stopscrew set improperly
h. Adjust stopscrew.
a. Loose manifold connections.
a. Tighten connections.
leak.
b. Damaged or improperly installed
b. Install correctly. Replace if
gaskets.
c. Restricted exhaust
a. Remove restrictions (Crimp) or
component
17. Low fuel pump pressure.
a.
Clogged gasoline tank cap vent.
b.
Fuel pump filter bowl loose.
c.
Clogged fuel pump filter.
d.
Damaged or improperly installed
d. Install properly or replace gasket
bowl gasket.
e. Leaky fuel lines or fu line
e. Inspect, replace broken pieces
connections.
18. No oil pressure.
a. Stop engine immediately and fill to
prescribed level with OE as
shown on lubrication order. In-
spect for oil leaks while operat-
ing engine.
b. Inaccurate oil pressure gage
b. Replace pressure gage. Normal
pressure at idling speed is 20
to 25 pounds and at normal
speed 30 to 40 pounds (para
19. Engine uses too much oil.
a. Oil leak
a. Inspect for oil leaks, especially in
oil filter and cooler connections.
4-8