Compression Pressure - Yamaha EF3000iSE Service Manual

COMPRESSION PRESSURE

5. Measure:
• Compression
To measure the compression, set the
main switch to "START" "
to "ON" "
until the needle stops rising on the com-
pression gauge.
WARNING
To prevent sparking when cranking the
engine, ground the spark plug lead.
Testing steps (below minimum level):
• Squirt a few drops of oil into the cylinder.
• Measure the compression pressure again.
Reading
If higher than
without oil
If the same as
without oil
Testing steps (above maximum level):
• Check the cylinder head, valve surfaces,
and piston crown for carbon deposits.
6. Install:
• Spark plug
• Spark plug cap
7. Install:
• Panel 4
Refer to "COVERS, PANELS, AND
CAPS".
2-15
INSP
ADJ
" and pull the recoil starter
Standard compression pressure:
400 ~ 600 kPa
2
(4 ~ 6 kg/cm , 57 ~ 85 psi)
Diagnosis
• Worn cylinder, piston, and
piston ring
• Defective piston, ring(s),
valve(s), and cylinder
head gasket
• Improper valve timing and
valve clearance
Spark plug:
18 Nm (1.8 m · kg, 13 ft · lb)
" or set it