Power Unit; Checking The Compression Pressure - Yamaha E60HWD Service Manual

POWR

Power unit

Checking the compression pressure

1. Start the engine, warm it up for 5 min-
utes, and then turn it off.
2. Remove the clip from the engine stop
lanyard switch.
3. Remove the spark plug caps and all
spark plugs, and then install the special
service tools into a spark plug hole.
cC
Before removing the spark plugs, blow
compressed air in the spark plug well to
clear out any dirt or dust that may fall into
the cylinder.
Compression gauge:
90890-03160
4. Fully open the throttle, and then crank the
engine until the reading on the compres-
sion gauge stabilizes.
NOTE:
Do not pull the choke knob when checking
the compression pressure.
Minimum compression pressure
(reference data):
540 kPa (5.4 kgf/cm
5-5
Power unit
6F650010
2 , 76 psi)
5. If the compression pressure is below
specification and the compression pres-
sure for each cylinder is unbalanced, add
a small amount of engine oil to the cylin-
ders, and then check the compression
pressure again.
NOTE:
9 If the compression pressure increases,
check the pistons and piston rings for wear.
Replace if necessary.
9 If the compression pressure does not
increase, check the cylinder head gasket,
and cylinder head. Replace if necessary.
69D5G11