MAZDA 626 1987 Workshop Manual

4A FUEL SYSTEM
CARBURETOR
Removal
Remove in the sequence shown in the figure.
1. Secondary air hoses (If equipped) and air
cleaner
2. Water hoses
3. Fuel hose
4. Vacuum hoses
76G04A-027
5. Accelerator cable
6. Connector
7. Carburetor
8. PTC heater (If equipped)
9. Gasket (If equipped)
Installation
Install the reverse order of removal, referring following points.
1. Check for fuel leaks.
2. Check the vacuum hose installation.
3. Check the idle speed and idle mixture (Refer to page 4A—38).
4. Warm up the engine to the normal operating temperature and check that fuel level is at the center
of the float level indicator window.
4A—26

FUEL SYSTEM 4A
Disassembly
FE and F8 (General, ECE, Hong Kong, and Singapore)
76G04A-028
Disassemble in the sequence shown in the figure.
1. Lever
2. Secondary diaphragm
3. Choke breaker diaphragm and thermo wax
(If equipped)
4. Choke opener and bracket (If equipped)
5. Air horn
6. Float
7. Needle valve
8. Accelerator pump
9. Slow fuel cut solenoid valve
10. Idle-up solenoid valve and idle switch
(If equipped)
11. Air bleeds and jets
12. Injector weight
13. Primary venturi and nozzle
14. Secondary venturi and nozzle
15. Main body
16. Throttle body
4A—27

4A FUEL SYSTEM
FE 8Valve (Except General) and F6
76G04A-029
Disassemble in the sequence shown in the figure.
1. Lever 8. Solenoid valve* and idle switch (If equipped)
2. Air horn, choke breaker diaphragm, and 9. Air bleeds and jets
choke opener (If equipped) 10. Injector weight
3. Float 11. Primary venturi and nozzle
4. Secondary diaphragm 12. Secondary venturi and nozzle
5. Needle valve 13. Main body
6. Accelerator pump 14. Throttle body
7. Slow fuel cut solenoid valve
* Solenoid valve:
Coast enrichment solenoid valve FE 8 Valve—Unleaded fuel
Coasting leaner F6 Singapore
4A-28

FUEL SYSTEM 4 A
Assembly [FE and F8 (General, ECE, Hong Kong, and Singapore)]
Assemble in the sequence shown in the figure, referring to the assembly note for specially marked parts.
1. Throttle body
2. Main body
3. Secondary ven-
turi and nozzle
4. Primary venturi
and nozzle
5. Injector weight
Q. Air bleeds and
jets
7. Idle-up solenoid
valve and idle
switch (If
equipped)
8. Slow fuel cut
solenoid valve
9. Accelerator
pump
10. Needle valve
11. Float
12. Air horn
13. Choke opener
and bracket (If
equipped)
14. Choke breaker
diaphragm and
thermo wax (If
equipped)
15. Secondary di-
aphragm
16. Lever
76G04A-030
Assembly note
Air bleeds and jets
1. Step jet and plug
2. Secondary step air bleed (No. 1) (Fixed type)
3. Secondary main air bleed
4. Secondary main jet
5. Power jet
6. Primary main jet
7. Primary main air bleed
8. Primary slow air bleed (No. 1)
9. Primary slow jet and plug
10. Primary slow air bleed (No. 2)
76G04A-031
4A—29

4A FUEL SYSTEM
[FE 8Valve (Except General) and F6]
Assemble in the sequence shown in the figure, referring to the assembly note for specially marked parts.
1. Throttle body
2. Main body
3. Secondary ven-
turi and nozzle
4. Primary venturi
and nozzle
5. Injector weight
©Air bleeds and
jets
7. Solenoid valve
and idle switch
(If equipped)
8. Slow fuel cut
solenoid valve
9. Accelerator
pump
10. Needle valve
11. Secondary di-
aphragm
12. Float
13. Air horn, choke
breaker di-
aphragm, and
choke opener (If
equipped)
14. Lever
'3
©
76G04A-032
Assembly note
Air bleeds and jets
1. Step jet and plug
2. Secondary step air bleed (No. 1) (Fixed type)
3. Secondary main air bleed
4. Secondary main jet
5. Power jet
6. Primary main jet
7. Primary main air bleed
8. Primary slow air bleed (No. 1)
9. Primary slow jet and plug
10. Primary slow air bleed (No. 2)
76G04A-033
4A-30

FUEL SYSTEM 4A
76G04A-034
Inspection
Note
a) Clean all parts with carburetor cleaner and
dry with compressed air.
b) Do not use a wire to clean the jets.
Check the following and replace any faulty parts.
1. Damaged air horn, main body, or throttle body
2. Improper operation of the choke valve or throttle
valve
3. Damaged float
4. Needle valve damage or improper seating
5. Clogged or damaged jet or air bleed
6. Damaged piston cup in the accelerator pump
7. Weakened or broken spring
8. Damaged diaphragm
9. Improper solenoid operation
76G04A-191
Primary throttle valve
(0.248—0.327 in)
When secondary throttle valve
begins to open
Secondary Throttle Valve
1. Check the clearance between the primary throttle
valve and wall when lever A contacts lever B.
>
L_ Clearance:
7.3—8.3 mm (0.248—0.327 in)
7.3—8.3 mm
76G04A-035
3. If not within specification, adjust it by bending
lever A.
76G04A-036
4 A—31

4A FUEL SYSTEM
76G04A-037
Float Level
Caution
This adjustment must be made without the
gasket on the air horn.
1. Turn the air horn upside-down and allow the float
to lower by its own weight.
2. Measure clearance H between the float and the
air horn.
Clearance H: 12.5 mm (0.49 in)
3. If not as specified, bend the float seat lip A to adjust.
4. Turn the air horn to the normal position and allow
the float to lower by its own weight.
5. Measure clearance L between the bottom of the
float and the air horn.
Clearance L: 44 mm (1.73 in)
6. If not as specified, bend the float stop B to adjust.
76G04A-038
76G04A-039
Fast Opening
F6 and FE 8Valve (Except General)
1. With the choke valve fully closed, measure the
clearance between the primary throttle valve and
the wall of the throttle bore.
Specification:
Engine Spec. Clearance mm (in)
F6 General and
Singapore 1.40—1.76
(0.055-0.069) FE 8Valve Middle East and
Unleaded Fuel
1.40—1.76
(0.055-0.069)
2. If not within specification, carefully bend the con-
necting rod to adjust.
4A—32

FUEL SYSTEM 4A
76G04A-040
76G04A-041
Clearance
® J t'YCL ® J
V hi /®
'-v
76G04A-042
Fast Idle Opening
FE and F8 (General, ECE, Hong Kong, and Sin-
gapore)
Adjustment of fast idle opening is normally un-
necessary.
But if it is necessary, adjust it as shown.
1. Before adjustment, let the carburetor set at 25WC
(77°F) for at least 1 hour.
2. Check that the center of the cam lever aligns with
the mark (25°) on the fast idle cam.
3. If not as specified, adjust it by turning the adjust
screw.
4. Measure the throttle valve clearance between the
throttle valve and wall with a wire gage.
Specification
Spec. General, ECE, Hong Kong,
and Singapore
Transmission MTX ATX
Clearance mm (in) 0.48—0.64
(0.019-0.025)
0.56—0.72 (0.022-0.028)
5. If not as specified, adjust it by turning the fast idle
adjust screw.
Unloader System
Only FE and F8 (General, ECE, Hong Kong, and
Singapore)
1. Open the primary throttle valve fully.
2. Measure the choke valve clearance.
Clearance-
1.68—2.14 mm (0.066—0.084 in)
3. If not as specified, adjust it by bending tab A.
Slow Fuel Cut Solenoid Valve
1. Start the engine, and run it at idle.
2. Disconnect the connector of the carburetor.
3. Check that the engine stops.
4. If the engine does not stop, replace the slow fuel
cut solenoid valve.
76G04A-043
4A-33

4 A FUEL SYSTEM
76G04A-044
76G04A-045
76G04A-046
Choke Breaker Diaphragm
1. Warm up the engine to the normal operating tem-
perature, then stop the engine.
2. Set the choke valve to the fully closed position.
3. Apply 400 mmHg (15.7 inHg) vacuum to the di-
aphragm.
4. Measure the clearance between the choke valve
and air horn with a wire gauge.
Cl68r8ncG'
2.45—3.11 mm (0.096—0.122) FE, F8
1.68—2.14 mm (0.066—0.084 in) F6
5. If not within specification, adjust by bending the
lever.
Choke Opener
ECE, Hong Kong, Singapore, and Middle East
1. Warm up the engine to the normal operating tem-
perature, then stop the engine.
2. Set the choke valve to the fully closed position.
3. Apply 400 mmHg (15.7 InHg) vacuum to the di-
aphragm.
4. Measure the clearance between the choke valve
and air horn with a wire gauge.
Specification Clearance mm (in)
ECE, Hong Kong, and Singapore
(Except F6 MTX) 3.7—4.0 (0.15—0.16)
Middle East 3.3—3.6 (0.13—0.14)
F6 Singapore MTX 3.2—3.5 (0.13—0.14)
5. If not within specification, adjust by bending the
connecting rod.
76G04A-047
4A-34

FUEL SYSTEM 4 A
76G04A-048
76G04A-049
FUEL PUMP
Inspection
Fuel pressure
1. Disconnect the hose at the carburetor and connect
a fuel pressure gauge.
2. Disconnect the fuel return hose from the fuel pump
and plug the fuel pump return pipe as shown in
the figure,
3. Measure the pressure while the engine is idling.
Replace the pump, if necessary.
FE & F8 (ECE,
Hong Kong,
Singapore)
Others
Pressure kPa
(kg/cm2, psi)
20—29 (0.2-0.3, 2.8-4.3)
20-26
(0.20-0.27,
2.8-3.8)
Flow rate (volume)
1. Disconnect the carburetor fuel hose and insert the
end into a measuring breaker.
2. Disconnect the fuel return hose from the fuel pump
and plug the fuel pump return pipe as shown in
the figure.
3. Start the engine and measure the amount of fuel
pumped per minute.
Volume: More than 860 cc (52.5 cuin)/min
Removal
1. Remove in the following order.
(1) Fuel outlet hose
(2) Fuel inlet hose
(3) Fuel return hose
(4) Fuel pump
(5) Gasket
(6) Insulator
(7) Gasket
76G04A-050
Installation
Install in the reverse order of removal.
Caution
a) Replace the gasket whenever the fuel pump
is replaced.
b) Be sure to connect the hoses in the correct
positions.
Check for leaks.
76G04A-051
4A—35
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