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CHK
ADJ
MEASURING THE COMPRESSION PRESSURE
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a. Set the main switch to “ON”.
b. With the throttle wide open, crank the
engine until the reading on the compression
gauge stabilizes.
WARNING
_
To prevent sparking, ground all spark plug
leads before cranking the engine.
NOTE:
_
The difference in compression pressure
between cylinders should not exceed 100 kPa
(1 kg/cm
2
, 1 bar).
c. If the compression pressure is above the
maximum specification, check the cylinder
head, valve surfaces and piston crown for
carbon deposits.
Carbon deposits → Eliminate.
d. If the compression pressure is below the
minimum specification, pour a teaspoonful
of engine oil into the spark plug bore and
measure again.
Refer to the following table.
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Compression pressure
(at sea level)
Minimum
1,350 kPa
(13.5 kg/cm
2
, 192 psi)
Standard
1,450 kPa
(14.5 kg/cm
2
, 206 psi)
Maximum
1,500 kPa
(15.0 kg/cm
2
, 213 psi)
Compression pressure
(with oil applied into the cylinder)
Reading Diagnosis
Higher than with-
out oil
Piston ring(s) wear
or damage
→
Repair.
Same as without
oil
Piston, valves, cyl-
inder head gasket
or piston possibly
defective
→
Repair.