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3-18
CHK
ADJ
MEASURING THE COMPRESSION PRESSURE
7. Measure:
8
compression pressure
Out of specification
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Refer to steps (c)
and (d).
Compression pressure (at sea level)
Minimum
827 kPa (8.27 kg/cm
2
, 400r/min)
Standard
950 kPa (9.5 kg/cm
2
, 400r/min)
Maximum
1064 kPa (10.64 kg/cm
2
, 400r/min)
*****************************************************
a. Set the main switch to “ON”.
b. With the throttle wide open, crank the en-
gine until the reading on the compression
gauge stabilizes.
w
To prevent sparking, ground the spark plug
lead before cranking the engine.
c. If the compression pressure is above the
maximum specification, check the cylinder
head, valve surfaces, and piston crown for
carbon deposits.
Carbon deposit
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Eliminate.
d. If the compression pressure is below the
minimum specification, pour a teaspoonful
engine of oil into the spark plug bore and
measure again.
Refer to the following table.
Compression pressure
(with oil applied into the cylinder)
Reading
Diagnosis
Higher than without oil
Piston ring wear or damage
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Repair.
Same as without oil
Piston, valves, cylinder head gasket or piston pos-
sibly defective
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Repair.
*****************************************************
8. Remove:
8
compression gauge
9. Install:
8
spark plug
12.5 Nm (1.25 m • kg, 9ft • lb)
10. Connect:
8
spark plug cap
T
R
.
.