Mazda RX7. Manual - part 33

 

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Mazda RX7. Manual - part 33

 

 

CARBURETOR - NIKKI 4-BBL

Article Text (p. 5)

1983 Mazda RX7

For www.iluvmyrx7.com    

Copyright © 1998 Mitchell Repair Information Company, LLC

Sunday, August 26, 2001  05:52PM

Fig. 6:  Hot Start Assist Cable Adjustment

         THROTTLE OPENER

         A/C Models Only
         1) Turn off all accessories. Remove fuel filler cap.
Disconnect and plug idle compensator tube at air cleaner. Connect
tachometer to engine and warm engine to normal operating temperature.
         2) Disconnect electrical connector from air switching
solenoid valve (Gray color). Disconnect and plug vacuum sensing tubes
from leading vacuum control units on distributor.

Fig. 7:  Throttle Opener Adjustment (A/C Models Only)

         3) Turn off air conditioner switch. Disconnect electrical
connector from air conditioner solenoid. Connect battery power to one
terminal in connector and ground other terminal.
         4) Throttle opener should operate and engine speed should
increase to 1150-1250 RPM in Neutral. If engine speed is not to
specification, turn adjusting nut shown in Fig. 7.

         CHECKING ALTITUDE COMPENSATOR

CARBURETOR - NIKKI 4-BBL

Article Text (p. 6)

1983 Mazda RX7

For www.iluvmyrx7.com    

Copyright © 1998 Mitchell Repair Information Company, LLC

Sunday, August 26, 2001  05:52PM

NOTE:    Altitude compensator must be checked at altitudes of
         1640-4920 feet.

         1) Remove air cleaner and start engine. Engine should run
smoothly at specified idle. Place finger over slow port on carburetor
air horn; idle speed should drop.
         2) If idle speed did not drop, remove compensator valve and
blow through both ports. Air should pass through compensator valve.
If not replace altitude compensator valve.

Fig. 8:  Adjusting Accelerator Cable and Pedal Height

         ACCELERATOR CABLE ADJUSTMENT

         1) Check accelerator pedal position. Pedal should be
1.5-1.9" (37-47 mm) lower than brake pedal. See Fig. 8. If necessary,
adjust nut "A" to obtain correct position.
         2) Cable free play at carburetor should be .04-.12" (1-3
mm). To adjust free play, adjust nut "B". Depress accelerator to
floor and check that throttle valves are wide open. If necessary,
adjust stop bolt "C".

         OVERHAUL

NOTE:    Disassembly and assembly procedures will vary from vehicle
         to vehicle due to emissions equipment and type of
         transmission. Some carburetors may not have all parts
         referred to in the following procedures.

         DISASSEMBLY

         1) Remove vacuum sensing tubes for altitude compensator

CARBURETOR - NIKKI 4-BBL

Article Text (p. 7)

1983 Mazda RX7

For www.iluvmyrx7.com    

Copyright © 1998 Mitchell Repair Information Company, LLC

Sunday, August 26, 2001  05:52PM

valve and choke delay valve. Remove choke heater lead, choke
diaphragm No. 2 vacuum sensing tube and altitude compensator valve.
         2) Remove throttle opener and bracket assembly, No. 1 choke
diaphragm vacuum sensing tube, dashpot diaphragm and bracket assembly
(Man. Trans. only) and throttle return spring.
         3) Remove sub-return spring, return spring bracket, bi-metal
spring housing and bracket assembly. Remove split pin and fast idle
rod, hot start assist lever spring and bracket assembly and choke
lever.
         4) Remove the choke return diaphragm and bracket, No. 2
choke diaphragm and air horn assembly from main body. Disconnect
float pin and remove float, needle valve, spring, valve stem and
retainer.
         5) From main body, remove accelerator pump rod, secondary
throttle valve rod, throttle sensor and main body attaching bolts.
Remove main body from throttle body.

Fig. 9:  Removing Jets and Air Bleeds

         6) Remove secondary throttle attaching screws, cover, return
spring, pin and clip, diaphragm, housing and gasket. Remove "E" clip,
washer and shaft, accelerator pump lever, attaching screws, cover,
diaphragm and return spring.
         7) From main body, remove accelerator pump injection screw,
nozzle, gasket, weight, outlet check valve, check valve seat, weight
and inlet check valve. Remove retainer, blind plug and washer,
primary main jet and secondary main jet.
         8) Remove air bleeds and jets. See Fig. 9. Using a hacksaw,
remove idle limiter cap by cutting through limiter cap, 0.4" (10 mm)
from cap end. Remove and discard mixture adjusting screw and spring.

         CLEANING & INSPECTION

CARBURETOR - NIKKI 4-BBL

Article Text (p. 8)

1983 Mazda RX7

For www.iluvmyrx7.com    

Copyright © 1998 Mitchell Repair Information Company, LLC

Sunday, August 26, 2001  05:52PM

         1) Wash all parts in clean solvent and clear all passages
using compressed air. Never use wire for cleaning jets, orifices or
passages. Inspect air horn, main body and throttle body for cracks or
breakage.
         2) Inspect choke shaft and throttle shaft for wear, linkage
and connecting rods for bends, and return springs for damage. Inspect
float, needle valve and seat and strainer for damage.
         3) To check air vent solenoid for proper operation, apply
battery voltage to solenoid valve, valve stem should pull into valve
body. Replace solenoid if it fails to operate properly.

         REASSEMBLY

         1) To reassemble, reverse the disassembly procedure, using
new gaskets. Avoid mixing primary and secondary system parts having
similar shape. When installing new mixture screw, seat lightly and
back out 3 turns for initial adjustment.
         2) When installing bi-metal spring housing, fit choke shaft
lever to bi-metal spring by closing choke valve and pulling vacuum
diaphragm shaft. Before installing air horn, make necessary float
adjustments.

         ADJUSTMENT SPECIFICATION

CARBURETOR ADJUSTMENT SPECIFICATIONS

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Application                                              Specification

RX7
 Float Level In. (mm)  ..........................  .61-.65 (15.5-16.5)
 Float Drop In. (mm)  .........................  1.98-2.02 (50.5-51.5)
 Choke Linkage In. (mm)  ........................  .040-.047 (1.0-1.2)
 Accel. Cable Free Play In. (mm)...................  .04-.12 (1.0-1.3)
 Choke Valve Opening In. (mm)......................  .22-.24 (5.5-6.2)

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