Yanmar 3TNV Series Service Manual page 60

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( )
No extreme injection angle difference( )
Finely atomized spray
Excellent spray departure
(c) 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.
(d) Nozzle punch mark
45
2. Inspection and Adjustment