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Defender 90 / 110 / 130. Manual - part 52

ETROL FU

EL SYSTEM

OVERHAUL FUEL LIFT PUMP

DISMANTLE

5 .

Turn, whilst pressing down the metal part

of the

diaphragm through

90" in either direction and

withdraw the diaphragm and spring.

6 .

Unstake the

oil seal housing and

the oil

scal and retainer.

1. Remove the sediment bowl, where fitted, and

collect the filter gauze and sealing washer.

2. Mark the upper and lower halves of pump casing to

ensure correct alignment

on reassembly.

3. Remove top cover fixing screws, and while pressing

diaphragm tab against pump body, lift top cover
clear.

Using a small chisel,

staking from the

rocker arm retainers.

8. Withdraw the retainers.
9. Withdraw the rocker arm.

10. Withdraw the rocker arm pin and washers.
11.

the operating link.

12. Withdraw

rocker

arm spring.

If necessary remove the valves by cutting away the

retaining stakes with a scraper. Warm the top
cover, note the position

of the valves and withdraw

them from the cover.

...

. .

. . . .

13. It is unlikely that

t h e

hand priming mechanism will

ever require replacement, but

i t

can be removed by

filing the hexagon each side

of the operating lever

and springing the hand lever clear, withdraw the
cork washers and hand rocker.

PETROL

FUEL

SYSTEM

14.

16.

17.

18.

19.

20.

Inspect

29.

Fit the filter gauze and sealing ring

pumps with

sediment bowl and fit the  bowl  and secure with  the
retaining  clip.  Ensure  that  the  bowl  and  seal  are
located  squarely.

not overtighten securing n u t

to prevent cracking the bowl.

Clean

all parts

paraffin (Kerosene) and examine

for wear and renew as necessary including all
gaskets

Sediment bowl filter disc must be free

of damage

and fit tightly around inlet neck

of upper casing.

Renew diaphragm assembly if any sign of

hardening, cracking

or porosity is present.

Only very slight wear should be tolerated at the

rocker arm

face, pivot pin, operating link

and diaphragm pull rod slots.
Springs should be renewed ensuring that the
correct type are used.
Test valves

for air tightness, by suction.

Check upper and lower casing flanges for

distortion, using a straight edge.

Test fuel pump

Immerse pump

a bath of paraffin and operate

rocker arm several times to flush.

31. Hold the pump clear

of the bath and continue to

operate the rocker arm until the pump is empty,
then place

a finger over the inlet port and operate

rocker arm several times.

distinct suction should

be heard when the finger is removed from the inlet
port, denoting that a reasonable degree of suction
has been developed.

32. Place a finger over the outlet port and again

Assemble

21. Fit the rocker arm spring.
22. Fit

t h e operating link.

23. Fit the rocker arm pin and washers.
24. Fit the rocker arm assembly to the pump body and

secure with the retainers and stake.

25. Fit the

oil seal and retainer and secure by staking.

operate the rocker arm. Air pressure should be felt
for two to three seconds after rocker movement  has
ceased.  Build  up  the  air  pressure  in  the  pump
again,  and  with  the  finger  held  firmly  over  the

outlet,

the pump completely

in the

paraffin bath, then observe

joint face edges for

signs of air leakage.

26.

To refit the diaphragm assembly, hold the pump
body with the diaphragm

spring

position,

and the rocker arm held outwards. Position the
diaphragm over the spring with

t h e

flattened end

the pull rod

in line with the slot in the

link.

Push t h e diaphragm inwards and turn to lock.

Fit the inlet and outlet valves and secure by

staking.

28.

Place top cover assembly

position, aligning the

marks made before dismantling. Fit securing

screws, but  do not tighten  at this stage; using hand
priming  lever,  fully  depress  diaphragm  and  fully
tighten  securing screws.
The

diaphragm

edges

should

approximately flush

the outer edge

of the

pump joint faces when

OVERHAUL ELECTRICAL FUEL PUMP

NOTE: The electrical components of the pump

are

sealed and cannot be repaired.

DISMANTLE

1. Remove pump from the vehicle, and clean outside

of pump before dismantling.

2. Release the end-cover from the bayonet fixing.
3. Remove the following items:

filter and seal

b) magnet
c) gasket

Pump piston assembly

4. Carefully prise out the retaining clip.
5 . The following parts will then bc released:

a) plain washer
b) rubber seal

c) one-way valve

Withdraw t h e piston return spring with the piston.
If t h e piston remains

in the pump tube, hold the

pump body vertically (in the fitted position) and
tap t h e closed end until the piston is released from
its magnetic hold and drops out.

NOTE: The piston is fitted with a one-way valve
which should not be disturbed.

con

ued

PETROL FUEL

SYSTEM

7. Remove the short rebound spring.
8. Clean all components in paraffin.

Immerse pump body

petrol and use air-line

inside pump tube.

NOTE: The fuel filter assembly, instructions 2 and
3, can be carried out with the pump on the vehicle.

ASSEMBLE

Pump piston assembly

Fit the short rebound spring.

11.

Fit the return spring over the opposite end of the

12. Slide the piston assembly into the pump body.
13. Fit the following items:

piston.

a) plain washer

rubber seal

c) one-way valve

14.

Secure

t h e

assembly

with

the spring clip.

Fuel filter assembly

Fit the filter and seal.

16.

Fit the magnet.

17. Fit the end cover with a new gasket.

18. Fit pump to vehicle and ensure that the earth

connection lead and its mounting point is clean.

CARBURETTER

FOUR

CYLINDER

ENGINE

OVERHAUL

DESCRIPTION

The twin bored 32

DMTL Weber carburetter is a

fixed choke instrument with a staggered throttle
opening. The carburetter is divided, operationally, into
two sections namely the primary and secondary
carburetters with 32

and 34

bores respectively.

The delayed throttle opening occurs

in the secondary

carburetter.
The primary  carburetter, which  incorporates  fuel  and
air  jets  for  idling,  is  used  for  starting,  and  normal
running,  up  to  approximately  two  thirds  throttle
opening.  Shortly  before  this  stage  the  secondary

carburetter butterfly will begin

to open and become

increasingly  more  involved  as  the  throttle  is  opened
further.  To  ensure  a  smooth  transition  during  the
various  stages of  throttle  opening  both  sections of  the

carburetter contain progression fuel and air jets and

ports.

prevent fuel vaporisation and air locks

i n the system

fuel is continuously pumped back to the fuel tank from

the

carburetter float chamber. The top

float

chamber is

so designed that fuel is drawn off from

main stream via the needle valve as dictated by the fuel

level

in the chamber.

DISMANTLE

Remove the carburetter.

2. Disconnect the fast idle cam assembly.
3. Disconnect the

link.

4. Disconnect

pull-down lever and linkage.

5. Remove the top cover from

t h e

carburetter body.

Withdraw the float pivot and detach the float.

7. Remove the needle valve attached to the float tag.

Remove

discard the gasket from the top cover.

9. Withdraw

t h e

needle valve housing.

10. Remove the fuel

plug and filter.

11.  Remove the pull-down capsule.
12.  Remove the fuel cut-off solenoid and valve.
13.  Withdraw  both  ‘primary’  and  ‘secondary’ idle

holders noting their positions for ease of

14. Withdraw both ‘primary’ and ‘secondary’ main jet

assemblies, comprising main jet, emulsion tube
and air correction jets.

15. Lift out the pump jet.

16. Remove the accelerator pump cover, diaphragm,

gasket and spring.

Detach the economy pump assembly, comprising

cover, spring and diaphragm.

18. Remove the idle mixture control screw. When the

adjustment

tamper-proofed, the tamper-

proofing cap must be removed to expose the screw.

continued

535

19-49

Content .. 50 51 52 53 ..