Yanmar 3JH4E Service Manual page 49

[Informative: Fuel injection valve structure]
2) Spray pattern inspection
After adjustment to the specified valve opening
pressure, use a nozzle tester and check the spray
pattern and seat oil-tightness.
a) Seat oil tightness check
• After injecting a few times, increase the pressure
gradually. Hold the pressure for about 5 seconds
at a little before the valve opening pressure of
1.96 MPa (20kgf/cm
does not drip from the tip end of the nozzle.
• If extreme oil leak from the overflow joint exists
during injection by the nozzle tester, check after
retightening. If much oil is leaking, replace the
nozzle assembly.
F.O. return pipe joint
Nozzle holder
Pressure adjusting shim
Nozzle spring
Nozzle spring seat
Pin
Valve stop spacer
Nozzle valve
Nozzle body
Nozzle case nut
Tightening torque:
39.2 to 44.1 N m (4 to 4.5 kgf m)
2
), and check to see that oil
Nozzle
Normal
(Uniform spray pattern from each nozzle)
33
2. Inspection and Adjustment