Yanmar 2YM15 Service Manual download pdf (Page 60)

2. Inspection and adjustment

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

), and check to see

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(

Θ)

• Finely atomized spray

• Excellent spray departure

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.

(Abnormal spray pattern)

(Normal spray pattern)

=5 10

(Nozzle valve sliding check by gravity)

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Yanmar 2YM15 Service Manual Page 60