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Defender 90 / 110 / 130. Manual - part 55

ROL FUEL SYST

Mixture setting and balance carburetters

17. Remove balancer. With the mixture setting and

carburetter

balance

correctly

adjusted

the

difference in engine

with the tool

605330

on o r off will be negligible, approximately plus or
minus 25

8. Remove the piston damper plug, and using special

tool

adjust the mixture. Locate the outer

sleeve of the tool to engage a machined slot to

the air valve twisting. Turn the inner tool

clockwise

enrich the mixture and anti-clockwise

to weaken it. After every adjustment the tool

should be removed from the carburetter to allow
engine to stabilise. Run engine at 2000

aid stabilisation.

When t h e mixture is correctly adjusted, the engine

speed will remain constant

may fall slowly a

small amount as the air valve is lifted.

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..:

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10. Check, and if necessary, zero the

balancing

tool 605330.

11. Place balancer on the carburetter adaptors,

that there are

air leaks. If the engine

stalls

or decreases considerably in speed,

mixture is too rich.

t h e

engine speed increases,

the mixture is too weak.

12. If necessary, remove balancer and re-adjust

the

mixture, then refit the tool.

13. Check balancer gauge reading.

14.

I f the gauge pointer is in the ‘zero’ sector, no

adjustment is required.

15.

If the gauge pointer moves

t h e

right, decrease

the

air-flow through the left-hand carburetter by

air-flow through the right-hand

turning clockwise the slow running screw. Reverse
the

procedure if the pointer moves to the left.

16.

If the engine idle speed (slow running) rises too
high or drops too low during balancing adjust to

the correct idle speed, whilst maintaining the gauge
pointer in the zero sector.

unscrewing

screw

increase

the

I...

Check

CO level

Use a proprietary

infra-red exhaust gas

analyser.

18. Insert the probe of the analyser as far as possible

into the exhaust tail pipe, start

t h e

engine and

allow a one to one and a half

minute stabilisation

period.

19. Check that the correct idle speed (slow running) is

maintained and observe the C O reading against
that given in the data section.

If necessary re-adjust

the

setting to achieve the correct C O level.

PETROL

FUEL SYSTEM

Adjust throttle linkage

Fast idle adjustment

20. On the left-hand carburetter, place a

in)

feeler between the underside

of the

roller on the countershaft lever and the throttle
lever.

21. Apply

to t h e throttle lever to hold

the

feeler.

22. Tighten the screw

secure the throttle adjusting

lever, then withdraw the feelcr.

26.

The fast idle adjustment is  pre-set  on  the left-hand
carburetter  and  should  not  normally  require
adjustment.  If adjustment  is  required,  the  correct
procedure  is

to remove the left-hand carburetter

and carry out instructions

69 under carburetter

overhaul. Alternatively the fast idle can be
approximately set by pulling the choke cable until
the mark

on the cam is in-line with t h e head of the

adjusting screw. Slacken the locknut and adjust the

screw against the cam until the correct idle speed

achieved see ‘Engine tuning data’. Tighten the
locknut.

23.

On the right hand

place a

in) feeler between the

leg of the fork on

the adjusting lever and the pin o n the throttle
lever.

24. Apply light pressure

t o

the linkage to hold

feeler.

25. Tighten the screw to secure the throttle adjusting

lever, then withdraw

fcclcr.

27.

Fit t h e air cleaner elbows.

28. Remove the piston damper

plug on both

carburetters and replenish

t h e

damper reservoir

with S.A.E.20 oil to within 12

in) from

top of

tube and refit damper plug.

PETROL

FUEL

SYSTEM

CARBURETTER OVERHAUL

S.U. HIF 44

Right hand

DISMANTLE

1. Remove the carburetters from the engine and clean

the exteriors with a suitable solvent.

2. Remove the two nuts and spring washers and

withdraw

the air intake adaptor and joint washer.

3. Unscrew and remove

piston damper assembly

and drain the oil.

4. Remove the three screws and lift-off the suction

chamber complete with piston and spring.

Remove the spring clip from the top of t h e piston

rod and withdraw the piston and spring.

6. Unscrew the fuel metering needle guide locking

screw. If

needle cannot be removed from the

piston with the fingers, hold

needle as close to

the piston as possible,

in a soft jawed vice and with

a sharp pull withdraw the needle, guide and spring

assembly.

Remove

four screws and withdraw the float

chamber cover plate and scaling ring.

8. Remove the jet adjusting lever retaining screw and

spring.

9. Withdraw the jet complete with the bi-metal lever

and seperate the lever from the jet.
Unscrew and remove

float pivot spindle and

plain washer, and remove the float.
Lift-out the needle valve.

12. Unscrew and remove the needle valve and filter.
13. Unscrew and remove

jet bearing nut.

14. Invert the carburetter body to allow the jet bearing

to fall out.

If the bearing sticks, carefully tap it out

from t h e bridge side.

15. Remove the piston guide peg.
16. Remove

t h e

suction chamber-to-body sealing ring.

17. Unscrew and remove the mixture adjusting screw

and seal. Use thin nosed pliers to finally withdraw
the screw.

18. Bend-back

t h e

cam lever

n u t

lock tabs and remove

the nut and lock washer.

19. Remove the cam lever and spring.

20. Remove the end seal cover and seal.
21.

Remove t h e two screws and withdraw the cold start

valve body and seal together with the valve spindle.
Also collect the paper joint washer.

22. Note t h e position of the throttle levers and return

spring.

Bend-back the lock washer tabs and remove the
throttle lever nut.

24. Remove

the lock washer, bush washer and throttle

actuating lever.

25.

the

spring

and

throttle adjusting leaver from the throttle butterfly
spindle and remove the return spring.

26. Hold the butterfly

and mark the relationship

of the butterfly to the carburetter flange.

27. Remove the butterfly two retaining screws and

withdraw the butterfly from the spindle.

28. Withdraw the throttle butterfly spindle from the

carburetter body together with the two seals.

29. Clean all components with petrol or de-natured

alcohol ready for inspection.

not use abrasives

for the removal of stains or deposits.

INSPECTION

30. Examine the throttle spindle and bearings for

excessive axial clearance.

31. Check the float needle and seating for wear and the

float for punctures and renew if necessary.

32. Check the condition of all rubber seals,

‘0’

rings

and joint washers and renew

if necessary. The float

cover plate seal must be renewed.

33. Examine the carburetter body for cracks and

damage.

34. Ensure that the inside

of the suction chamber

clean and

fit

piston into the chamber without

the spring. Hold t h e assembly horizontally and spin
the piston.

The piston should spin freely

in the

suction chamber without any tendency to stick.

35. Inspect the metering needle for wear, scores and

distortion. Check also that

has the correct

designation number

Engine Tuning Data,

Section

05.

36. Examine the bi-metal jet lever for cracks.
37. Check all springs for cracks and distortion.

ASSEMBLE

Fit throttle butterfly

38. Fit the throttle spindle

t h e

carburetter body and

insert the throttle disc into

spindle in its original

position.  Secure  the  disc  with  new  screws  and
ensure  that  before  tightening  the  throttle  disc  is
correctly  positioned  and closes properly.  Splay the
split ends of the screws to prevent turning.

39.

Fit new seals to both ends of t h e throttle spindle

ensuring that they are fitted the correct way round.

Fit

cold start assembly

40.

Fit a new

ring to the valve body and assemble

t h e

valve spindle

the valve body.

41.

Fit

a new paper j o i n t washer to the valve noting

that the half-moon cut-out

the washer is

clearance for the top retaining screw.

continued

PETROL FUEL

SYSTEM

42. Fit the starter assembly to the carburetter body and

secure with the two screws.

43.

Fit the end seal and cover.

44. Fit the return spring.
45. Fit the cam lever and tension the spring.

Fit a new

lock washer and secure with the nut and bend the
tabs over a convenient flat.

46. Adjust the coils of the spring, if necessary, to

prevent coil binding.

KEY TO

S.U.

COMPONENTS

2.
3.
4.
5.
6.

7.
8.
9.

11.

12.

14.
15.
16.
17.

18.
19.

20.
21.
22.
23.

25.
26.
27.
28.
29.
30.
31.

Piston damper.
Spring clip.
Suction chamber.

Piston.

Piston spring.
Suction chamber retaining screws -3

off.

Needle retaining screw.
Needle bias spring.
Needle guide.
Needle.
Suction chamber sealing ring.

Throttle adjusting scrcw and scal.

Piston key and retaining screw.
Mixture adjusting screw and seal.
Carburetter body.

Throttle butterfly and retaining screws.
Throttle spindle.
Throttle spindle

2 off.

Float chamber.
Float chamber cover and retaining
Float chamber cover seal.

Jet

Jet bearing.

bearing

n u t

Bi-metal jet lever.

Jet retaining and adjusting screw and spring.
Float needle.
Float needle seat.
Float needle seat filter.
Float
Float pivot spindle.

32.  Cold start and cam lever assembly.
33.  Throttle adjusting lever and lost motion  assembly.
34.  Throttle actuating lever.
35.  Bush washer.
36.  Throttle  lever  assembly  retaining  nut  and  lock

washer.

continued

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Content .. 53 54 55 56 ..