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

Page 189

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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