Service manual

G420F(FE) Service Manual Chapter 2. Recommended Maintenance 19
3) Install the oil filler cap.
4. Start engine and check for oil leaks.
5. Recheck engine oil level.
Checking Compressed Pressure
1. Prior to inspection, check that the engine oil,
starter motor and battery are normal.
2. Start the engine and run it until the engine coolant
temperature reaches 80 ~ 95°C.
3. Stop the engine and disconnect the ignition coil
and air cleaner element.
4. Remove the spark plug.
5. After opening the throttle valve completely, crank
the engine to remove foreign material from the
cylinder.
CAUTION
At this time, necessarily screen the spark plug
hole with a rag. Because hot coolant, oil, fuel,
and other foreign material, being penetrated in
the cylinder through cracks can come into the
spark hole during checking compressed
pressure.
When cranking the engine to test compressed
pressure, necessarily open the throttle valve be-
fore cranking.
6. Install the compression gauge to the spark plug
hole.
7. With the throttle valve opened, crank the engine
to measure the compressed pressure.
Standard 15kg/㎠
Standard(250~400rpm)
Limit 14kg/㎠
8. Follow the procedures (no.6-7) to each cylinder
and check that compressed pressure values of all
cylinders are within the limit.
Limit 1.0kg/㎠
9. If any of all cylinders is out of limit, add a small
amount of engine oil to the spark plug hole, and
re-proceed the procedures (no.6-7) to the cylinder.
At this time, if the compressed pressure is increased,
it means that the piston, piston ring or cylinder
surface are worn or damaged, and if the
compressed pressure is decreased, it means that
the valve is clogged, the valve contact is faulty, or
the pressure leaks through gasket.
CAUTION
If a large amount of incomplete combustion
gaso-line comes into the catalytic converter,
emergency such as a fire can occur due to
overheating. So this job should be done quickly
with the engine not operated.