Land Rover Defender 90 110 Workshop Book 2 Rover

							PETROL FUEL SYSTEM 119 
Float chamber assembly 
54. Fit the needle valve and new  washer. 
55. Locate the spindle in the float  arm  and fit the 
assembly  into the retaining  clips. 
seating  and 
thc float tab is contacting  the  needle. 
Measure  the dimension 
A between the carburetter 
gasket  face and 
the highest  point on the floats.  The 
correct  measurement  should be 17 to 
18 mm (0.67 
to 
0.71 in).  Adjust  by bending the float  tab. This 
dimension  must  be  the same  for both  floats.  The 
float  carrier  tab must  be maintained  at  right  angles 
to  the needle 
in the  closed position. 
57. 
Fit the  float  chamber  and new  gasket  and  evenly 
tighten  the retaining  screws. 
56. Invert the  carburetter so that  the  needle  is on  its 62 
- .. .. .. . .. 
ST1123M 
Air valve  and diaphragm 
58. Fit the diaphragm  to the air valve with  the inncr tag 
locating  in the  air valvc recess. 
59. 
Fit the  diaphragm  retaining ring and  secure  with 
the four screws. 
60. Fit the  metering needle into the air v2!ve and 
secure  with the locking  screw. 
61. Insert the air valve  and needle into the carburetter 
and  locate 
the diaphragm  outer tag  into  the recess 
in the carburetter  body. 
62. Fit the spring  and top cover  and secure  with the 
four screws. 
63. 
Fit the  damper. 
---- ST7 1 17M 
Temperature compensator 
64.  Clean  the  carburetter  and compensator  mating 
faces. 
65. Fit a new  inner and  outer rubber  washer and securc 
the  temperature compensator  with thc two  screws 
and shake
-proof washers. 
Fast idle adjustment - L.H. carburetter only 
66.  Slacken  the fast idle adjusting  screw. 
67.  Hold  the cold  start  cam  lever 
in the  maximum 
position. 
68.  Adjust 
thc fast idle  adjusting  screw against  the cam 
lever  until there  is 
0,61 to 0,66 mm (0.024 to 
0.026  in) gap  between 
the top edge  of the  throttle 
butterfly  and 
the carburetter  barrel wall. Use feeler 
gauges 
or a 0,65 mm diameter (No. 72)  drill  to 
measure  the gap. 
69.  Secure the  locknut on  the fast  idle  adjusting  screw 
without disturbing  the adjustment. 
11  
						

							I 19 I PETROL FUEL SYSTEM 
V8 ENGINE ZENITH CARBURETTERS 
TUNE AND ADJUST 
Tamper
-proofing 
These  carburctters  may be externally  identified by a 
tamper
-proof  sealing  tube fitted  around  the slow 
running  adjustment  screw. 
The  purpose  of these  carburetters  is to  more  stringently 
control  the air fuel  mixture  entering  the engine 
combustion  chambers and, in consequence,  the exhaust 
gas  emissions  leaving 
the engine. 
For this reason  the only  readily  accessible  external 
adjustment  is to  the  throttle  settings for idle  and  fast 
idle  speed  and, for the  former  setting 
will require  the 
use 
of a  special  tool to prevent  breaking  the tamper- 
proof  seals. 
* CAUTION:  Unauthorised  breaking of tamper-proofing 
devices,  adjustment  of carburetter  settings 
or the fitting 
of  incorrectly  related parts may render  the vehicle  user 
liable  to legal  penalties  according  to local  territory 
legislation. 
Whenever  adjustments  are made  to the  settings  of 
tamper
-proof  or emission  specification  carburetters an 
approved  type CO meter  must be used  to ensure  that the 
final  exhaust  gas analysis  meets with local  territory 
requirements. 
Emission  Specifications 
All carburetters  fitted to the  Land-Rover  conform  at 
the time of manufacture  to particular  territory 
requirements 
in respect  of exhaust  and evaporative 
emissions  control. However,  in some  cases changes  to 
the  basic  carburetters  may have  been necessary  to 
achieve  this. 
Service  tools: 
605330 - Carburetter  balancer 
MS80 - Mixture adjusting  tool 
MS86 
or B25243 - Tamper-proofed  throttle 
adjustment  tool 
The  service  tool 
605330 carburetter  balancer must be 
used  to adjust  the carburetters.  Primarily, this 
instrument  is for  balancing  the air
-flow  through  the 
carburetters,  but it also  gives  a good  indication 
of the 
mixture setting.  Investigation  has shown  that incorrect 
mixture  setting causes either stalling  of the  engine 
or a 
considerable  drop in engine rev/min if the  balancer  is 
fitted  when  the mixture 
is too  rich  or a considerable 
increase 
in rvt (anin when  used wit;] tule mixture  setting 
too  weak. 
Br\)re balancing  the  carburetters  it is  most 
important  therefore that the following  procedure  be 
carried  out: 
Slow running  (idle) adjustment 
1. Check  that the throttle  control between  the pedal 
and  the carburetters  is free  and has no tendency 
to 
stick. 
2. Check  the throttle  cable setting  with the throttle 
pedal 
in the  released  position.  The throttle  linkage 
must  not have  commenced  movement, but 
commences  with the minimum  depression  of the 
pedal. 
3. Run  the engine  until it attains  normal  operating 
temperature;  that is, thermostat  open. 
4.  Remove 
the air  cleaner  elbows. 
5.  Slacken  the screws  securing  the throttle  adjusting 
levers  on both  carburetters  to allow  independent 
adjustment. 
r . 
$,;; 
6. 
7 
Start  the engine  and check  the idle  speed  using a 
reliable  proprietary  tachometer. 
If necessary, adjust the slow running  screw to give 
the  correct  idle speed,  see Engine  tuning data. If a 
tamper
-proof  sleeve  is fitted  over this screw  the 
slow  running  speed can 
only be adjusted  using 
special  tool MS86 
or B25243. $3, .._ : -r C. 
continued 12  
						

							PETROL FUEL SYSTEM 119 I 
4:.;.:
						

							PETROL FUEL SYSTEM 
Adjust throttle linkage  Fast 
idle adjustment 
20. On  the  left-hand carburetter,  place a 0,15 mm 
(0.006 in) feeler  between  the underside of the 
roller  on  the countershaft  lever and  the  throttle 
lever. 
21. Apply pressurc to the throttle  lever to hold the 
feeler. 
22.  Tighten  the screw 
to secure  the throttle  adjusting 
lever, then withdraw  the feelcr. 
20 
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 
66 - 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 the head  of the 
adjusting  screw. Slacken  the locknut  and adjust  the 
screw  against  the cam 
until the correct  idle speed is 
achieved  see ‘Engine  tuning  data’. Tighten  the 
locknut. 
23. On the  right  hand carburettcr, place  a 0,15 mm 
(0.006 in) feeler  between  the left leg of the  fork  on 
the  adjusting  lever and the pin 
on the  throttle 
lever. 
24. Apply  light pressure to the linkage  to hold thc 
feeler. 
25. Tighten  the  screw to secure the  throttle  adjusting 
lever, then withdraw 
thc fcclcr. 
ST1 
27. Fit the air cleaner  elbows. 
28.  Remove  the piston  damper 
plug on both 
carburetters  and replenish 
the damper  reservoir 
with  S.A.E.20  oil to within  12 
mm (0.5 in)  from 
thc top of thc tube  and refit  damper  plug. 
STl130M 
14  
						

							PETROL FUEL SYSTEM 1191 
6 ;: CARBURETTER OVERHAUL - S.U. HIF 44 - 
5 ;.’‘ 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 
the piston damper  assembly 
and  drain  the oil. 
4.  Remove  the  three  screws and lift
-off the suction 
chamber complete  with piston and spring. 
5. Remove  the  spring  clip from  the  top of the piston 
rod  and  withdraw  the piston  and spring. 
6.  Unscrew  the fuel  metering  needle  guide  locking 
screw.  If 
the needle  cannot  be  removed  from  the 
piston  with the fingers,  hold 
the 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. 
7. Remove the 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. 
10. Unscrew  and remove the float  pivot  spindle  and 
plain  washer, and  remove the float. 
11. Lift-out the  needle valve. 
12.  Unscrew  and remove  the needle  valve and filter. 
13.  Unscrew and  remove 
thc 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 
the bridge  side. 
15. Remove the piston guide peg. 
16.  Remove 
the 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 the cam  lever nut 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 the two screws  and withdraw  the cold  start 
valve  body and seal  together  with the valve  spindle. 
Also  collect  the paper  joint washer. 
22. Note the position of the throttle  levers and  return 
spring. 
23. Bend-back  the lock  washer  tabs  and  remove  the 
throttle  lever 
nut. 
24. Remove the lock  washer,  bush washer  and throttle 
actuating  lever. 
25. Re!eise the thro!t!e retErn spring and remmve the 
throttle  adjusting  leaver from  the  throttle butterfly 
spindle  and remove  the return  spring. 
26.  Hold  the butterfly 
closed 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. 
Do 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 is 
clean and fit the piston  into the  chamber  without 
the  spring. Hold 
the 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 
it has the  correct 
designation  number 
- see 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 to the carburetter body and 
insert  the throttle  disc 
into the 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 the throttle  spindle 
ensuring that  they are fitted  the correct  way round. 
Fit cold start  assembly 
40. Fit a new ‘0’ ring to the  valve  body and  assemble 
the valve spindle to the valve  body. 
43 4.0 
ST1873M 
41. Fit a new  paper joint washer  to the  valve  noting 
that  the  half
-moon cut-out in the washer is 
clearance  for the  top  retaining screw. continued 
15  
						

							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. 
CT?374M 45 
KEY TO S.U. CARHURETTER COMPONENTS 
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
21. 
22.  23. 
24 
25. 
26.  27. 
28.  29. 
30. 
31. 
16 
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 
scals - 2 off. 
Float  chamber. 
Float  chamber  cover and retaining 
SCICWS. 
Float  chamber  cover seal. 
Jet 
asscm bl y . 
Jet  bearing. 
let bearing nut 
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 
f-. -..-. ...I ... ... -=LA#  
						

							PETROL FUEL SYSTEM 
.. - . ;; . .. 
19 
17  
						

							El PETROL FUEL SYSTEM 
Fit throttle lever assembly 
47. Fit the return  spring so that  the  longest leg rests 
against 
the throttle adjusting  screw housing. 
48.  Fit the  throttle  adjusting  lever and lost motion 
assembly  and tension  the return spring. 
49. 
Fit the  throttle actuating  lever. 
50. Fit the bush washer  and lock  washer. 
51. Fit and tighten  the special  nut and  bend  the lock 
tabs  over  a 
convcnient flat. 
Fit jet and  float assembly 
52. Fit the jet bearing, long  end towards the  float. 
53. Fit the jet bearing  nut. 
54.  Clean 
or renew  the filter  and fit the float  needle 
seat. 
55. 
Fit the  needle valve,  spring loaded  pin uppermost. 
56. Fit the  float  and secure  with the pivot  pin. 
57.  Hold  the carburetter 
in the inverted  position so 
that the needle  valve is  closed  by the  weight of the 
float  only.  Check  using a straight  edge  that 
the 
point on the float,  arrowed on the illustration,  is 
1.0 to 1.5 mm (0.04 to 0.062 in) below  the level of 
the float  chamber  face? dimension  ‘A’. 
58.  Adjust  the float  position  by carefully  bending the 
brass  pad 
until the correct  dimension  is achieved. 
After adjustment,  check  that the float  pivots  freely 
about  the spindle. 
56 A 
/ 
T 
I I I ST1876M 
18 continued  
						

							PETROL FUEL SYSTEM 
._ I .. e.;;.!!,{: 59. Assemble the jet to the  bi-metal  jet lever  and 
ensure  that the 
jet head  moves  freely in the 
cut-out. 
60. Fit the jet and  bi-metal  jet lever  to the  carburetter 
and  secure  with the spring  loaded  jet retaining 
screw. 
(. :. z: , . , . . .. , , . .. 
Fit piston and suction chamber 
64. Fit the  needle,  spring and guide  assembly  to  the 
piston  ensuring that  the  etched  arrow head on the 
needle  locating  guide is aligned  between  the piston 
transfer  holes, as  illustrated. 
65. Secure and ensure  that when the screw  is tightened 
the  guide 
is flush  with the piston  and  that the  scrcw 
locates  in 
the guide slot. 
ST1879M 1 
66. Fit the piston key to the  carburetter  body using  a 
new  screw.  Tighten 
thc scrcw and  splay the end. 
67. Fit a new  suction  chamber  sealing ring to the 
groove 
in the carburetter  body. 
68. TO prevent the piston spring  being wound-up 
during  assembly, 
tcmporarily fit the piston  and 
suction  chamber  less 
thc spring to the  body,  and 
pencil  mark the  relationship  of 
the chamber  to the 
body.  Remove  the suction  chamber  and 
fit the 
spring  to the  piston.  Hold  the  suction chamber 
above 
the spring  and piston,  align the pencil  marks 
and  lower  the chamber 
over the spring and  piston, 
taking 
care not  to rotate  the suction  chamber. 
Secure  the  chamber to the  body 
with the  three 
scrcws, tightening evenly  and check  that  the piston 
moves  freely. 
69. Hold the piston  at the  top of its stroke  and fit the 
spring clip. 
70. Fit the piston  damper. 
71. Using a new joint washer, fit the air intake  adaptor 
and secure 
with thc two  nuts  and spring  washers. 
72. Fit the carburetters  to the inlet manifold  ensuring 
that  the 
joint washers, dcflector and insulator  are 
fitted 
in the  sequence  illustrated.  The insulator 
must  be fitted  with the  arrow 
hcad uppermost  and 
pointing  inwards towards  the manifold.  Secure 
with  the four  nuts  and  spring washers  and  tighten 
evenly 
to the  correct  torque. 
A.  Joint  washer. 
B. Deflector-teeth pointing  inwards. 
C. Joint washer. 
D. Insulator. 
E. Joint washer. 
continued 
19  
						

							PETROL FUEL SYSTEM 
72 
ST1880M 
73. Connect the linkages and top-up the  carburetter 
dampers 
with a  recommended oil to  the  top  of the 
hollow  piston rod. 
74. Tune and adjust  the carburetters. 
ST1914M / 
TUNE  AND ADJUST - SU HIF 44 CARBURETTERS 
Special  tools: 
Carburetter  balancer 605330 or B89 
Non-dispersive infra-red exhaust  gas anaiyscr 
General  Requirements  Prior to Tuning  Carburetters. 
Accurate  engine speed is essential  during carburetter 
tuning, 
therefore the  distributor  pick up air  gap  and 
ignition  timing must be checked  together  with the 
vacuum  advance  system. 
Whenever  possible the ambient  air temperature 
of the 
tuning  environment  should be between 
15 to 26°C (60 
to 80°F). When  checking  engine speed, use an 
independent  and accurate  tachometer. 
Idling  adjustments  should be carried  out on a fully 
warmed  up engine,  that is, at least 
5 minutes  after the 
thermostat  has opened.  This should  be followed  by 
a 
run of one minute  duration  at an  engine  speed of 
approximately 2,500 revhin before  further 
adjustments 
or checks  are carried  out. This  cycle  may 
20 
be repeated  as often  as required. It is important  that 
the  above 
cycle is adhered  to, otherwise  overheating 
may  result  and settings  may be incorrect.  The piston 
dampers  must always  be kept  topped
-up with  the 
correct  grade of oil. 
Before  any attempt  is made 
to check  settings  a 
thorough  check should  be carried  out to ensure  that the 
throttle  linkage between  the pedal  and carburetters 
is 
free  and has no tendency  to stick.  Ensure  that the 
choke  control  lever 
is pushed fully down. 
NOTE: References  to left  and  right  hand are as from  the 
drivers  seat. 
TAMPER 
-PROOFING 
To comply  with E.C.E.  regulations  the idle  speed  and 
mixture  adjusting  screws must be tamper 
- proofed 
following  any adjustments. 
A red blanking  plug; Part 
number 
- JZX 1258 must  be fitted  into the mixture 
screw resess and  a red  cap; Part  number JZX 1197 
fitted  over the idle  adjustment  screw (throttle - 
adjustment  screw). 
e: 
continued 
:3 ,,. ... ,