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12) Inspection of Compression Pressure
1. Start and idle engine for 5 minutes to warm up, and then stop.
2. Shift gear into neutral (N).
3. Remove lock plate (of stop switch lanyard) from stop switch.
6. Fully open throttle a, crank engine until compression gauge
indication 1 stabilizes, and then measure compression
pressure.
7. If compression pressure is below specified value, put small
amount of engine oil into cylinder, and perform the test again.
Clean areas around spark plug on the
cylinder before removing spark plugs to
prevent dirt from entering cylinder.
Compression Gauge :
P/N. 3AC-99030-0
Compression Pressure (Reference) :
1.13 MPa (164 psi) [11.5 kgf/cm
2
]
• If compression pressure increases after the
above measure, check pistons and piston rings
for wear. Replace if necessary.
• If compression pressure does not increase
after the above measure, check valve
clearances, valves, valve seats and cylinder
sleeve. Adjust or replace if necessary.
To prevent accidental start of the engine,
remove lock plate (of stop switch lanyard)
from stop switch before measuring
compression pressure.
4. Remove plug cap and then spark plug.
5. Install compression gauge 1 to plug hole.
• Compression pressure is affected much by
cranking speed, and normally changes
approximately 10%.
• Do not pull choke knob when measuring
compression pressure.
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