Fuel system, Adjusting fuel injector pressure – Cub Cadet Yanmar 3TNV72 User Manual
Page 189

FUEL SYSTEM
7-28
TNV IDI Service Manual
Fuel Injectors
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 7-34).
(c) Release the valve. It should fall smoothly to
its seat by its own weight.
Figure 7-34
Replace the fuel injector assembly if it fails any
inspection.
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 7-35, (4)).
1 – Return Fuel Fitting Nut
2 – Fuel Return Fitting
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 7-35
The injection pressure will change by
approximately 100 - 142 psi (0.69 - 0.98 MPa;
7 - 10 kgf/cm
2
) for every 0.004 in. (0.1 mm) shim
thickness.
See the parts catalog for available shims.
1. Disassemble the fuel injector assembly. See
Disassembly and Inspection of Fuel Injectors
on page 7-27.
2. Remove or add adjusting shims as needed.
3. Reassemble the fuel injector assembly. See
Reassembly of Fuel Injectors on page 7-29.
Fuel Injector Shim Kit
Yanmar Part No. 129901-53800
(Includes one each of the following shims)
129901-53810
0.0039 in. (0.10 mm)
129901-53820
0.0079 in. (0.20 mm)
129901-53830
0.0118 in. (0.30 mm)
129901-53840
0.0157 in. (0.40 mm)
129901-53850
0.0197 in. (0.50 mm)
129901-53860
0.0205 in. (0.52 mm)
129901-53870
0.0213 in. (0.54 mm)
129901-53880
0.0220 in. (0.56 mm)
129901-53890
0.0228 in. (0.58 mm)
129901-53900
0.0315 in. (0.80 mm)
0001332A
0002093
0002214
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
TNV_IDI_ServiceManual_(3TNV72 for YN only).book 28 ページ 2007年11月29日 木曜日 午後2時58分