Land Rover Defender 90 110 Workshop Book 2 Rover

							PETROL FUEL SYSTEM 
TUNE AND ADdUST 
The following  instructions  apply to both carburetters 
unless  otherwise  stated. 
Before  commencing  the following  instructions,  remove 
the  air cleaner,  air intake  elbows,  mixture  adjustment 
screw  plug and mixture  screw cap. 
CARDURETTERBALANCE 
Using balancer 605330 
1. Disconnect  the interconnecting link between  the 
two  carburetters. 
Fit the balancer to the 
carburetter  intakes and ensure  that there  are no air 
leaks, 
if necessary,  zero the gauge with the 
adjustment  screw. 
2. Start the engine,  and if necessary allow it to reach 
normal  operating  temperature.  If 
the nccdle moves 
to  the  right,  decrease 
the air flow  through  the left 
hand  carburetter  by unscrewing  the idle  screw. 
Alternatively,  increase the air flow  through  the 
right  hand  carburetter  by screwing  down the idle 
screw.  Reverse  the procedure 
if the pointer  moves 
to  the  left.  Reconnect  the carburetter  inter
- 
connecting link. 
Using balancer B89 
3. Disconnect  the inter-connecting  throttle link 
between the two carburetters. 
4. Back-off the idle adjusting  screw on each 
carburetttcr,  clear of the 
throttlc Icver. 
5. Turn  each throttle  adjusting  screw so that it 
touches the throttle  lever. then turn the screws  by 
equal  amounts  to achieve  an approximate  idle 
speed  of 
700 to 800 rev/min. 
6. Press  the balancer  firmly over the carburetter 
intake.  Press 
or withdraw  the control  on the  side  of 
the  balancer  to adjust  the meter  needle  reading 
to 
approximately  half scale,  and note the reading. 
con t I n ued 
21  
						

							PETROL FUEL SYSTEM 
7. Without  altering the position  of the  balancer 
control,  place 
the balancer on the  second 
carburetter  intake  ahd  adjust  the idle screw  as 
necessary  to 
achicve the same  reading. 
. 
8. Alternatively,  adjust  and check  the balance of both 
carburetters  until  an idle speed 
of 700 to 
800 rev/min is obtained. 
9. Reconnect  the  throttle inter-connecting  link,  and 
again  check 
the idle spced and balance. 
Mixture  setting 
10. Ensure  that  the engine  is still  at normal operating 
temperature. 
11. Mark the relationship  of the  suction  chamber  to the 
carburetter  body,  remove  the  retaining screws and 
lift off the suction  chamber complete with pistons. 
12. 
To achieve  a datum  setting  for the  mixture  screw, 
turn 
it anti-clockwise until  the jct is level with the 
carburetter  bridge. Check by placing  a straight 
edge  across  the bridge  and adjust  as  necessary 
so 
that the jet just touches  the straight  edge. 
13. Refit the suction  chamber  and  piston,  evcnly 
tighten  the retaining screws.  Check that the piston 
moves  freely  without sticking. 
Top-up the piston 
damper. 
14. Turn  the mixture  adjustment  screw three and one 
half  turns  clockwise. 
15. Insert the probe  of an  infra-red  exhaust  gas 
analyser  as far  as possible 
up the  exhaust pipe,  start 
the engine  and allow a one  and one half minute 
stabilisation period. 
16. Adjust the mixture  screw on both carburetters  by 
equal  amounts,  rich or weak  to achieve 
a CO 
reading of 0.5 to 2.5%. 
17.  If after  approximately  two minutes the 
CO level  is 
not satisfactory  run the  engine  at 2000 rev/min for 
one  minute  to stabilise the 
cquipment, continue  the 
setting  procedure  until a 
stablc CO reading  of 0.5 
to 2.5% at an  idle  speed of 700-800 rev/min is 
obtained. 
/ ,I 
2 
ST1915M 
idle speed aiid :iiikage adjustmen? 
18. Check  that the engine  is at  normal  operating 
temperature. 
19. Slacken  the nut,  at the left hand  carburetter 
securing  the inter
-connecting link ball  to  the 
throttle  cam lever. r-; Y: / 
continued  
						

							PETROL FUEL SYSTEM 1191 
_,-
						

							19 PETROL FUEL SYSTEM 
SYMPTOM 
DIFFICULT STARTING WHEN COLD 
IIFFICULTSTARTING WHEN HOT 
ACK OF ENGINE  POWER 
:RRATIC SLOW-RUNNING  OR iTALLING ON DECELERATION 
:XCESSIVE FUEL CONSUMPTION 
V8 ENGINE CARBURETTER 
FAULT DIAGNOSIS 
POSSIBLE CAUSE 
Insufficient  choke action 
Fast  idle adjustment  incorrect 
Float  chamber 
level too IOW 
Carburetter llooding 
No fuel  supply to carburetter 
Choke  sticking  on 
Blocked  air cleaner 
Float  chamber  level 
too high 
No oil in damper or oil too thin 
Air  valve  sticking 
Water  in fuel 
Float level too low 
Incorrect  jet sctting 
Zarburctter air leaks 
Vlanifold air leaks 
lamper 
oil too thick. No oil in  damper 
4ir valve  sticking 
3locked air cleaner 
lamper 
oil too thick 
-,.-....--. I.. ... l:..*-,l -,.-I. .._^ *.-- IICVIICCLly U,U>CU CLLII,UIC;LLCI 
loat level too high 
Norn jets and necdlc 
ncorrect  needle 
:hoke sticking on 
 
?heck and refill to correct  level  with oil pecificd 
:lean and check  freedom 
:it new air clcaner elements 
Ceplace with correct grade 
.L--,. .IICCI rlllU --A ICICL .* >I\)W ,.I iith carburetter tune and iidjusr instructions 
:heck and reset float lcvcl 
kck and repiacc as ncccssary 
:heck needlc typc 
:heck to ensure choke is rcturning to fully ~ff position. rcxt as ncccssary 
re Engine Fault diapnci\is 
1Ul~ I-.. :.. 111 tlCL\IIULIIICL .,-..--, 4 .,.. ..^ 
24  
						

							PETROL FUEL SYSTEM El 
LAND ROVER 110 TWIN  TANK  INSTALLATION 
Description 
The  fuel system  includes two  fuel tanks,  one at the rear 
of the vehicle  and an  additional  fifteen  gallon 
(68,20 litres) capacity tank on the right-hand  side of the 
vehicle.  Both tanks  contain 
an electrically  operated 
submerged  fuel pump 
in addition  to  a fuel  level 
indicator  unit in each  tank.  An ignition  controlled 
switch 
on the control  panel enables  the driver to select 
the  tank  to be  used.  The switch  also energises the  fuel 
level  indicator  unit  of the tank  selected  and  records the 
fuel 
level on the  single  indicator  dial. When the ignition 
is switched  ‘on’ the pump in the selected  tank will draw 
fuel  into  the  carburetter  float chamber  via 
a paper 
element  type filter  and  a vapour  separator. 
To prevent 
fuel  vapourisation  and  air locks a 
spill return  system  is 
incorporated 
in the  fuel  pipe  layout to pass back  vapour 
and  excess  fuel from  the 
vapour separator to  the tank in 
use through a restrictor  and a solenoid  operated  valve. 
The  valve,  which  is 
encrgiscd by the  tank  selection 
switch,  closes the port  to the  tank  not 
in use  and 
simultaneously  opens the port  to 
the sclccted tank. The 
restrictor 
is necessary  to prevent  fuel by-passing  the 
carburetter  and flowing  back  to 
the selected  tank 
through the  spill return 
systcm. 
In addition,  a  non-return  valve is enclosed  inside  the 
hose  connection  of the  supply  pipe  from 
the rear and 
side  tanks 
to prevent  the  possibility of a back-flow of 
fuel along  the supply  lines to thc fuel tanks. 
ST1683M 
FUEL TANK SELECTION SWITCH 
A. Fuel  tankswitch 
.. 
.. 
LAND  ROVER 110 REAK  TANK  AND 90 SIDE TANK 
INSTAL1,ATION 
Description 
Fuel drawn  by the  electrically  operated in-tank pump, 
is  delivered 
to a paper  element  type filter.  Situated 
bencath the right-hand  front footwell  attached to a 
chassis  outrigger  from 
the filtcr, fuel enters a vapour 
separator  located 
on the left-hand  side of the  bulkhead 
in 
the engine  compartment.  Fuel finally cntcrs the 
carburetter  float chamber  from  the port at the  base  of 
the vapour  separator.  The vapour  separator  comprises 
part  of the  spill  return  system  and its purpose  is to 
prevent  fuel vapour  causing  air  locks 
in the supply  to 
the carburetter.  Vapour and excess  fuel flows back  into 
the file! tmk thro~gh 2 restricter fitted !e the spi!! 
return port on the  vapour  separator. The restrictor  is 
designed  to assist 
in maintaining  a constant  fuel  level in 
the vapour separator  bowl and to prevent  fuel  flowing 
back  to the tank  at the  same  rate as the  delivery. 
FUEL  FILTER 
A. Fuel “Iter 
*. From fuel pump to filter pipc C. From fuel filter  to carburetter  via vapour  separator 
25  
						

							PETROL FUEL SYSTEM 119 
. 
VAPOUR SEPARATOR 
A. Vapour separator 
B. Spill  return to side tank 
C. Restrictor  and spill  return  to solenoid  valve 
D. Outlet from separator to carburetter 
SPILL RETURN  SOLENOID VALVE 
A. Solenoid valve 
B. Spill  return to side tank 
C.  Spill  return  to rear  tank 
D. To carburetter  via filter and vapour  separator 
NON-RETURN VALVE 
A. Non-return valve 
B. Spring 
C. 
Ball 
We 8 ST1844M 
FUEL PUMP 
A. Pump  and motor 
B. Filter 
C. Gasket 
D. Electrical  terminals 
E. Outlet pipe 
F. Fixing plate to tank 
G. Plastic  tie  clip - See CAUTION - remove  and 
refit  pump 
27  
						

							PETROL FUEL SYSTEM 
LAND ROVER 110 TWIN TANK FUEL SYSTEM 
I 
28 ::  
						

							PETROL FUEL SYSTEM E[ 
LAND ROVER 110 TWIN TANK FUEL SYSTEM 
KEY TO FUEL LINE INSTALLATION 
1. In-tank  fuel pump- rear  tank. 
2. In-tank  fuel pump -side tank. 
3. Fuel  gauge  tank unit -rear tank. 
4. Fuel  gauge  tank unit -side tank. 
5. Spill return solcnoid. 
6. Fuel  filter. 
7. Fuel  supply  pipe - rear tank  to filter  via T-piccc. 
8. Pipe,  filter to vapour scparator. 
9. Vapour  separator. 
10. Vapour separator  outlet to carburetter. 
1 1. Spill return  pipe to fuel  tank  via restrictor  and solenoid  valve. 
12. Spill rcturn pipe to side tank  from  solenoid. 
13. Spill rcturn  pipe to rear tank  from  solenoid. 
14. Fuel filler - rear tank. 
15. Breather  pipc - rear tank. 
16. Fuel  filler - side tank. 
17. Breather  pipe - side tank. 
18. Drain  plugs side and rear tanks. 
19. Non  return  valve incorporated in hose. 
.!::.: ,.
						

							1191 PETROL FUEL SYSTEM 
LAND ROVER 110 BASIC FUEL SYSTEM 
1. In-tank fuel pump. 
2. Fuel gauge tank  unit. 
3. Fuel supply  pipe to filter via connector. 
4. Fuel filter. 
5. Fuel supply pipe filter  to vapour separator 
6. Vapour separator. 
7. Vapour separator,  outlet to carburetter. 
8. Spill  return  pipe to fuel  tank  via restrictor. 
9. Fuel  filler. 
10. Breather  hose. 
11. Restrictor. 
12. Fuel tank drain  plug. 
f. f