Page 171
CARBURETOR
Single-carburetor
REMOVING
1. Disconnect the inlet hose from the carburetor.
2. Disconnect the fuel line, throttle and choke control
cables and vacuum hose to the distributor.
3. Remove the screw for the dip stick tube.
4. Back off the four retaining nuts and lift off the carburetor.
DISASSEMBLY
1. Take off the vacuum chamber cover ( 1 ), see illustration, and take out the spring (2).
1
REMOVING THE FUEL NEEDLE STOP SCREW
s----f
9
REMOVING THE FUEL NEEDLE (as from 1977 model)
Tool 83 92 763 or 83 92 896 (Allen key)
Tool 83 93 035 (recessed slot)
S4456
4. Remove the screws (4), the plastic and metal washers
(5, 3) and the diaphragm (9).
5. Remove the float chamber (21 ).
6. Carefully disengage the float spindle from the bridge
and remove the float (20).
7. Up to and incl. model 1976:
Unscrew and remove the jet retainer (16) with adjusting screw (19), jet (15), spring (14), bushings (11 and
13), washer (10). Save 0-ring (12).
7. As from model 1977:
The jet is press-fitted in the carburetor and normally
need not be removed.
8. Remove the float valve and washer.
9. Remove the choke mechanism.
CARBURETOR
1. Vacuum chamber cover
2. Spring
3. Metal washer
4. Screw
5. Plastic washer
6. Vacuum piston
7. Locking screw
8. Fuel needle
9. Diaphragm
2. Remove the piston (6) with membrane (9).
3. Loosen the screw (7) and remove the fuel needle (8).
As from 1977 model the fuel needle sleeve should be
removed using the CO adjustment key.
SAAB
231-1
Page 172
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13-c
14~
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20
11
21
15-Jl
16
.17
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ll
19=1\
S 4457
CARBURETOR
*10. Washer
*11. Bushing
*12. 0-ring
*13. Guide bushing
*14. Spring
*15. Jet
S5604
* 16. Jet retainer
VACUUM PISTON WITH CIRCLIP AND ADJUSTING SCREW
,,
*17. 0-ring
*18. 0-ring
*19. Adjusting screw
20. Float
21. Float chamber
Assembly
1. Using a drift, press the adjusting screw with O-ring
into the piston.
2. Using a drift, fit a new circlip into the damper.
*Up to and incl. model 1976.
Wash carburetor parts with paraffin oil or gasoline.
NOTE
Use only paraffin oil for washing the diaphragm.
Avoid the use of volatile cleaning fluids such as trichloroethylene.
REPLACING THE ADJUSTING SCREW IN THE
VACUUM PISTON AS FROM 1977 MODEL
Removal
1. Using a drift, press out the adjustil')Q screw a few centimetres at the bottom of the piston.
2. Press in the adjustment screw again.
3. Turn the locking clip loose and remove it by means
of a bent piece of wire. The adjustment screw can
now be removed.
231-2
PRESSING THE CIRCLIP INTO THE DAMPER
SA..a
Page 173
CHANGING THE JET, AS FROM 1977 MODEL
CLEANING AND CHECKING
The jet is press-fitted in the carburetor housing and
should not be moved from the position in which it is
installed. However, the jet can be changed using tool
83 92 789 as follows.
1. Remove the carburetor and then take off the vacuum.
chamber cover and remove the vacuum piston and
float chamber cover.
Use compressed air to clean the holes in the valve plate of
the choke mechanism. Check that the diaphragm is undamaged. If the diaphragm is distended or burst it must be
exchanged for a new one. Check the fuel needle for wear;
if it is bent or worn, fit a new one. Check that all contact
and sealing surfaces are undamaged. Check that the choke
plate of the choke mechanism and the matching surface
of the carburetor housing are free from scratches. Clean
the temperature compensator and check that the valve
moves freely.
ASSEMBLING
1. Mount the diaphragm on the vacuum piston so that
the locating lip (see illustration) engages the corresponding recess in the piston and the inner edge fits
easily into the matching groove in the piston.
THE JET IS FITTED
Tool8392789
2. Press out the jet using tool 83 92 789.
3. Using the tool press in the new jet from the float
chamber side until the jet is 2.5 mm below the level
of the bridge in the carburetor housing. If you happen
to press the jet in too far, it can be pushed back from
above using the same tool.
FITTING THE DIAPHRAGM
NOTE
If the diaphragm is so distended that it will not fit
into the piston, exchange it for a new one.
MEASURING THE JET HEIGHT POSITION
CAUTION
Avoid resting any type of measuring tool against
the upper, inner surface of the jet when pressing
it into position. Even the slightest deformation of
the surface can affect the hole in the jet.
Place the plastic washer (5 , see illustration) and the
metal washer (3) carefully in position, lining up the
screw holes with those in the piston and diaphragm
without twisting the washer and matching the groove
in the washer to the locating edge of the diaphragm.
Secure the washers with the screws (4).
Fit the fuel needle as follows:
Up to and incl. model 1976:
Place the flat milled jacket surface of the spring housing so that it faces the stop screw, i.e. the needle
should spring away from the throttle valve when the
piston is fitted.
The needle should be fitted so that the sleeve (at the
recess for the plastic washer) is flush with the bottom
of the piston.
This position is the initial setting for subsequent COadjustment.
231-3
Page 174
Edge of needle sleeve flush
with bottom of piston
S 5606
Needle sleeve flush with
bottom of piston
S 5607
FITTING THE FUEL NEEDLE, AS FROM MODEL 1977
FITTING THE FUEL NEEDLE, UP TO AND INCL. MODEL
1976
As from model 1977:
a. Insert the spring housing of the needle in the vacuum piston. Screw the spring housing onto the
adjuster by turning the latter using the CO adjustment tool.
This position is the initial setting for subsequent COadjustment.
2. Up to and incl. model 1976:
Insert the adjusting screw (19) with a new O-ring (18)
in the jet retainer (16). Fit a new O-ring (17) ori the
jet retainer. See fig.
FITTING THE FUEL NEEDLE, AS FROM 1977 MODEL
Tool 83 92 763 or 83 92 896 (Allen key)
Tool 83 93 035 (recessed slot)
b. Screw in the stop screw so that the spring-loaded
locking pin presses against the spring housing.
c. Use the CO adjustment tool to turn the spring
housing so that the locking pin engages the milled
groove.
d. Tighten the stop screw.
e. Use the CO adjustment tool to adjust the height of
the needle so that the edge of the sleeve (at the
recess for th·e washer) is flush with the bottom of
the piston.
S4456
CARBURETOR
1. Vacuum chamber cover
2. Spring
3. Metal washer
4. Screw
5. Plastic washer
6. Vacuum piston
7. Locking screw
8. Fuel needle
9. Diaphragm
3. Up to and incl. model 1976:
Place the spring (14), guide bushing (13), bushing (11 ),
Place the spring ( 14), guide bushing ( 13), bushing ( 11),
O-ring (12) and aluminium washer (10) on the jet (15)
and install the complete assembly together with the .
jet retainer ( 16) and adjusting screw ( 19) in the carburetor housing. (Figures refer to illustration on previous page.) Screw in and tighten the jet retainer.
231-4
SA.Ml
Page 175
4. Up to and incl. model 1976:
Screw in the adjustment screw until the top of the jet
is at a level 0.098 ± 0.008" (2.5 ± 0.2 mm) below the
level of the jet bridge. Check the dimension by means
of vernier calipers or using tool 8393027. (If the jet is
set at exactly 0.098" (2.5 mm), then a quarter turn in
either direction is permitted during the subsequent
CO setting. One quarter turn equals 0.008" (0.2 mm~
vertical adjustment.)
5. Install the piston complete with diaphragm and spring
in the carburetor housing. Make sure that the outer lip
of the diaphragm engages the matching recess in the
housing. Place the vacuum chamber cover carefully in
position according to the markings. The groove and
locating rim should be a good fit; if not exchange the
diaphragm. Tighten the screws.
6. Mount the float (20) with spindle. The flat side of the
float faces away from the carburetor housing.
7. Check the float level as follows:
a. To check the float level the carburetor must be removed from the engine, and inverted with the float
chamber off.
b. For the level to be correct the highest point of the
float should be 0.63-0.67" (16-17 mm) above the
edge of the carburetor housing (see illustration)
when the float valve is closed. If the level is not correct, adjust by bending the tongue at the float valve.
FUEL HOLES IN CHOKE MECHANISM
ADJUSTMENT
Choke control
Check that the distance between the adjustment screw
on the throttle shaft carrier and the choke cam disc is
0.020-0.039" (0.5-1.0 mm). Make sure that the choke
control is pushed in and that the throttle disc is completely closed. See illustration.
MEASURING FLOAT LEVEL
NOTE
Do not bend the arm between the float and the
spindle.
8. Fit a new gasket and slide the float chamber on until
it cushions against the O-ring. First insert all screws
and give them a few turns, then push down the float
chamber until it butts firmly and tighten the screws.
9. Mount the choke mechanism. (If the mechanism has
been removed, fit the choke plate, choke shaft and
cam plate as illustrated.) 'fhe calibrated hole should
face away from the cable securing point on the cam
plate.
S 4460
ADJUSTING THE CHOKE CONTROL
Basic setting up to and incl. model 1976
The vertical location of the fuel jet in relation to the level of the jet bridge has been carefully tested in view of
the load conditions likely to be experienced. No further
adjustment of the jet screw - apart from the adjustments
described below - should be attempted. If additional adjustment should be required, the vertical position of the
fuel needle in the piston should be modified.
231-5
Page 176
1. Remove the vacuum chamber cover together with the
spring, and the vacuum piston and diaphragm.
2. Using a vernier or measuring tool 83 92 027, measure
the distance between the jet bridge and the jet and adjust to 0.098 in (2.5 mm).
ADJUSTMENTING
THE MAIN JET USING A VERNIER
KEEP THE NEEDLE PERPENDICULAR
OF THE PISTON DURING CHECKING
TO THE BOTTOM
Up to and incl. model 1976, a special adjusting tool, No.
83 92 995, with insert No. 83 93 001 (designed for twin
carburetors) and a set of feeler gauges, No. 83 93 019,
are available to facilitate adjustment of the fuel needle.
ADJUSTING THE JET USING TOOL 83 93027
3. Adjust the height of the fuel needle in the piston by
backing off the retaining screw and moving the needle
up or down.
.....
TOOL FOR ADJUSTING THE FUEL NEEDLE
Needle sleeveflush with
bottom of piston
Insert the vacuum piston into the tool, with the feeler
gauges inserted in the slots of the tool.
The tool is preset to 0.04 in. (1.0 mm) and consequently
0.04 in. (1.0 mm) feeler gauge will prov·ide the basic setting for the fuel needle (i.e. the needle sleeve flush with
the bottom of the piston).
If during subsequent adjustment of the CO setting it
proves necessary to lower the fuel needle, use a thicker
feeler gauge, and to raise the needle, use a thinner feeler
gauge.
S 5606
HEIGHT SETTING OF FUEL NEEDLE
231-6
SUB
Page 177
NOTE
If the adjustment screw seizes it can be difficult
to detect when the needle is lying in its highest
position, C. Should this be the case it is recommended that the vacuum pistons are removed for
basic setting.
In such a case the needle shoulder should be flush
with the bottom of the piston.
ADJUSTING THE FUEL NEEDLE
Tool 83 92 995
4. Fit the vacuum piston with the diaphragm, spring and
vacuum chamber cover.
Needle shoulder flush with
bottom of piston.
S 5607
Basic setting, as from model 1977
d. Rotate the screw 1 1/2 turns counter-clockwise.
The jet is fixed in the carburetor. Adjust the height of the
fuel needle by means of the special tool.
1. Remove the plastic cover and damper piston.
2. a. Insert the CO adjustment tool through the dash pot
onto the vacuum piston and adjusting screw.
THE ADJUSTMENT SCREW IS TURNED 1 1/2 TURNS
COUNTE A-CLOCKWISE
..\
3. Check the oil in the damper, topping up if necessary,
and then replace the cover with piston. Fine adjustment should be made during the subsequent CO-setting.
INSERTING THE TOOL THROUGH THE DAMPER
Tool 83 92 763 or 83 92 896 (Allen key)
Tool 83 93 035 (Recessed slot)
b. Use the sleeve of the tool to support the damper
piston to prevent the diaphragm being damaged.
c. Turn the adjusting key clockwise until resistance is
felt (needle i~ highest position).
r
CO setting
To obviate the possible influence of hydrocarbons on the
CO setting (caused by the presence of fuel in th~ engine
oil), the crankcase ventilation should be disconnected
while adjustment work is being carried out.
.....
231-7
Page 178
1. Preparing to measure the CO setting:
a. Run the engine until it is warm so that the CO reading (item 4) may be carried out after the radiator
fan has cut in for the second time.
b. Up to and incl. model 1977: Check that the preheater valve is in the "Summer" position.
c. Check that the choke control is fully depressed.
d. Check that the float chamber ventilation valve is
correctly adjusted.
e. Check that the ignition timing is set correctly.
f. Plug or clamp shut the vacuum hose to the vacuum
control unit on the distributor.
h. Plug the end of the vacuum hose to the EGR valve
where applicable.
2. Connect the CO-meter and tachometer.
S 5202
CHECKING THE CO-CONTENT
3. Set the idling speed to: up to and incl. Model 1976:
850 ± 50 rev./min.
As from model 1977: 2000 rev./min.
THE DISTRIBUTOR
HOSE CLAMPED
g. Disconnect the crankcase ventilation as follows:
ADJUSTMFNT
OF IDLING SPEED
4. Read off the CO-value.
CO setting with the crankcase ventilation, vacuum
controls and EGR disconnected
Up to and including 1976 model
As from 1977 model Sweden
As from 1977 model Europe
S6093
DISCONNECTION OF CRANKCASE VENTILATION,
FROM MODEL 1976
AS
1. The hose removed from valve cover
2. The small-bore hose plugged (as from model 1977)
3. Evacuation hose connected to valve cover
Evacuate the crankcase gases from the opening in the
valve cover by connecting a hose to the workshop's
evacuation hose, slightly behind the probe of the COmeter to ensure that the readings will not be affected.
231-8
max. 3.5%/850 rpm
1.75±0.25%/2000 rpm
1. 5± 1%/850 rpm
Up to and incl. model 1976:
To adjust the CO-setting, raise or lower the fuel needle
to increase or reduce the CO-value, respectively. Do
not turn the jet adjusting screw more than 1/4 of a
turn from the basic setting.
Page 179
Rotate clockwise (A) to increase CO-value (fuel needle
raised).
Rotate counter-clockwise (Bl to reduce CO-value (fuel
needle lowered).
5. Remove the plugs and connect up the crankcase ventilation, the EGR hose and the vacuum hose to the distributor.
6. Set the idling speed to 850 ± 50 rev/min.
7. Check the CO-value at idling speed. If the value exceeds 4.5 %, it is likely that fuel has penetrated the
engine oil, necessitating an oil change.
CAUTION
Check the calibration of the CO-meter regularly.
S 5612
THE FUEL NEEDLE IS RAISED OR LOWERED
As from model 1977:
To adjust, remove the damper piston which allows the
fuel needle adjustment screw to be rotated using the
CO adjustment tool. Support the vacuum piston by
means of the sleeve of the tool to prevent the rubber
diaphragm from being damaged.
CO SETTING ADJUSTMENT
Tool 83 92 763 or 83 92 896 (Allen key)
Tool 83 93 035 (recessed slot).
SA.Ml
231-9
Page 180
2
3
4
5
I
$.----
6·
1-:
16
19
20
S 5614
CARBURETOR
1. Cover with damper piston
2. Vacuum chamber cover
3. Spring
4. Washer
5. Diaphragm
6. Circlip
7. Adjustment screw
8. Fuel needle
231-10
9. Vacuum piston
10. Lock screw with spring loaded
plunge
11. Jet
12. Carburetor housing
13. Float valve
14. Float
15. Float chamber
16. Driver
17. Deceleration valve
18. Temperature compensator
19. Plug
20. Cold start device with cam disc
21. Arm, float chamber ventilation
22. Adjustment screw idling
23. Adjustment screw, float chamber
ventilation