Adjusting Fuel Injector Pressure - Yanmar 3TNV82A Service Manual

FUEL SYSTEM
6. Inspect the sealing surfaces (Figure 7-52, (2))
between the valve stop spacer and nozzle body
for nicks or scratches. Check the contact area
between the valve stop spacer and the nozzle
valve (Figure 7-52, (1)) for scoring, or pitting.
Use a magnifier glass to inspect the area.
(1)
(2)
Figure 7-52
7. Perform a nozzle valve slide test:
(a) Wash nozzle body and valve in clean diesel
fuel.
(b) While holding the nozzle body vertical, pull
the nozzle valve about 2/3 of the way out
(Figure 7-53).
(c) Release the valve. It should fall smoothly to
its seat by it's own weight.
Figure 7-53
8. Replace the fuel injector assembly if it fails any
inspection.
7-36
0001333A
0001332A

Adjusting Fuel Injector Pressure

The fuel injectors open when pressure reaches a
predetermined pressure threshold. They close
when the pressure is reduced below that threshold.
The pressure threshold can be adjusted by adding
or removing shims (Figure 7-54, (3)).
0002093
1 – Fuel Return Passage
2 – Injector ID Location
3 – Injector Body
4 – Pressure Adjusting Shims
5 – Spring
6 – Spring Seat
7 – Valve Stop Spacer
8 – Nozzle Valve
9 – Nozzle Body
10 – Nozzle Case Nut
Figure 7-54
The injection pressure will change by
approximately 275 psi (1.9 MPa; 19 kgf/cm
every 0.1 mm (0.004 in.) in shim thickness.
See the parts catalog for available shims.
TNV DI Service Manual
Fuel Injectors
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
0002093
2
) for