Operation Manual

ENGINE INSPECTION
5-1
EAS59C1501
ENGINE INSPECTION
EAS59C1502
MEASURING THE COMPRESSION PRES-
SURE
The following procedure applies to all of the
cylinders.
TIP
Insufficient compression pressure will result in
a loss of performance.
1. Measure:
• Valve clearance
Out of specification → Adjust.
Refer to “ADJUSTING THE VALVE
CLEARANCE” on page 3-5.
2. Start the engine, warm it up for several
minutes, and then turn it off.
3. Remove:
• Radiator cover
Refer to “GENERAL CHASSIS” on page
4-1.
4. Disconnect:
• Spark plug caps
5. Remove:
• Spark plugs
ECA13340
Before removing the spark plugs, use com-
pressed air to blow away any dirt accumu-
lated in the spark plug wells to prevent it
from falling into the cylinders.
6. Install:
• Compression gauge “1”
7. Measure:
• Compression pressure
Out of specification → Refer to steps (c)
and (d).
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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 compres-
sion gauge stabilizes.
TIP
The difference in compression pressure
between cylinders should not exceed 100 kPa
(1 kgf/cm², 14 psi).
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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8. Install:
• Spark plugs
Compression gauge
90890-03081
Engine compression tester
YU-33223
Standard compression pres-
sure (at sea level)
1950 kPa/470 r/min (19.5 kgf/
cm²/470 r/min, 282.8 psi/470 r/
min)
Minimum–maximum
1700–2180 kPa/470 r/min
(17.0–21.8 kgf/cm²/470 r/min,
246.1–316.8 psi/470 r/min)
Compression pressure (with oil applied into
the cylinder)
Reading Diagnosis
Higher than without
oil
Piston ring(s) wear or
damage → Replace.
Same as without oil Piston, valves or cyl-
inder head gasket
possibly defective →
Replace.
Spark plug
13 Nm (1.3 m·kgf, 9.4 ft·lbf)