Yanmar 3YM30 Sevice Manual page 55

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 (20 kgf/cm
that oil 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.
b) Spray and injection states
• Operate the nozzle tester lever at a rate of once or twice a second and check no abnormal
injection.
• If normal injection as shown below cannot be obtained, replace the fuel injection valve.
• No extreme difference in angle(
• Finely atomized spray
• Excellent spray departure
= 5 10
(Normal spray pattern)
3) Nozzle valve sliding test
Wash the nozzle valve in clean fuel oil. Place the
nozzle body vertically and insert the nozzle into the
body to about 1/3 of its length. The valve is normal
if it smoothly falls by its own weight into the body.
In case of a new nozzle, remove the seal peel, and
immerse it in clean diesel oil or the like to clean the
inner and outer surfaces and to thoroughly remove
rust-preventive oil before using the nozzle. Note
that a new nozzle is coated with rust-preventive oil
and is pasted with the seal peel to shut off outer
air.
Θ
)
40
2. Inspection and adjustment
(Abnormal spray pattern)
(Nozzle valve sliding check by gravity)
2
), and check to see