TM 5-3740-214-14
Table 5-3. Direct and General Support Maintenance Troubleshooting (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
ENGINE LACKS POWER (Continued)
b.
Check the spark plug visually. Replace it and go to Step 5, if there are:
(1)
Cracks in the insulator.
(2)
Electrodes worn so thin they cannot be regapped.
(3)
Oil fouling, soft, wet, oily deposits covering the insulator and the plug nose. If there is oil fouling,
go to Step 10.
(4)
Build-up of deposits between insulator and the plug shell.
(5)
Broken insulator or bent electrode.
NOTE
If the spark plug must be replaced, set the gap at 0.025 inches (0.64 mm).
Oil fouling is a sign of internal engine damage.
Figure 5-128. Spark Plug Gap
c.
Check the spark plug gap.
(1)
Reset the gap at 0.025 inches (0.64 mm) if necessary and go to Step 6d.
(2)
If the gap is ok, go to Step 6d.
d.
Check the spark plug for a spark.
(1)
Connect the spark plug wire to the spark plug and set the plug on a grounded part of the engine.
(2)
Turn the ignition switch ON.
(3)
Crank the engine by hand. When the points open and close, a spark will jump between the spark
plug electrodes.
5-118
