Compression Pressure Measurement - Yamaha WaveRunner FZR-GX1800 Service Manual

CHK
ADJ
Power unit
6
5

Compression pressure measurement

1. Measure:
1
TIP
Make sure that the battery voltage is more
than 12 V.
2
3
4
Measurement steps:
1. Place the watercraft in the water.
2. Start the engine, allow it to warm up for 5
3. Remove the engine cover 1, bolts 2,
TIP
• Slide the engine cover rearward, and then lift
the cover to remove it.
• Be careful not to get water or any other for-
eign substances in the spark plug holes.
4. Install the special service tools 5 and 6.
5. Crank the engine until the reading on the
6. Measure the compression pressure for all
7. If the compression pressure is below spec-
Higher than without
engine oil
Same as without
engine oil
3-13
• Compression pressure
Compression pressure
(reference data):
610 kPa (6.1 kgf/cm
minutes, and then stop the engine.
ignition coils 3, and spark plugs 4.
Compression gauge extension 5:
90890-06582
Compression gauge 6:
YU-33223/90890-03160
compression gauge stabilizes.
cylinders according to steps 4–5.
ification, squirt a few drops of engine oil
into the cylinder and measure again.
Compression pressure
(with engine oil added into the cylinder)
Reading
E
2
, 86.8 psi)
Check
Piston ring, and
piston
Valve clearance,
valve, valve seat,
cylinder head, and
cylinder head gasket
1
2
4
5
6
7
8
9