Checking The Compression Pressure; Checking The Oil Pressure - Yamaha F225A Service Manual

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 shut-off
switch on the remote control box.
3. Remove the ignition coil cover and all
spark plugs, and then install the special
service tools to each spark plug hole.
CAUTION:
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 1:
90890-03160
Compression gauge adapter 2:
90890-06563
4. Fully open the throttle, crank the engine
until the reading on the compression
gauge stabilizes, and then check the
compression pressure.
Minimum compression pressure
(reference data):
880 kPa (8.8 kgf/cm
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-
der, and then check the pressure again.
69J3D11
2
, 125 psi)
NOTE:
• If the compression pressure increases,
check the piston and piston rings for wear.
Replace if necessary.
• If the compression pressure does not
increase, check the valve clearance, valve,
valve seat, cylinder sleeve, cylinder head
gasket, and cylinder head. Adjust or
replace if necessary.

Checking the oil pressure

1. Place a rag under the oil pressure sen-
sor.
2. Remove the intake silencer and oil pres-
sure sensor, and then install an oil pres-
sure gauge 1 to the oil pressure sensor
installation hole.
NOTE:
Use a pressure gauge with an adapter that
has a 1/8 pitch thread.
3. Install the intake silencer.
CAUTION:
Do not start the engine when the intake
silencer is not installed.
4. Start the engine, warm it up for 5 min-
utes, and then turn it off.
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