Edelbrock 1901, 1990, 1920, 1910, 1921 User Manual

Page 1 of 4

Rev. 10/02

FIG. 1

FLOAT

SETTINGS

15/32”

25/64”

19/64”

REPLACEMENT Q-JET CARBURETOR

KIT INSTRUCTIONS

KITS #1920, 1921 & 1990

Performer Models 1901, 1902, 1903,

1904,1905,1906,1910

Please read these instructions carefully before attempting to rebuild your carburetor. Make sure to refer to your carburetor Installation Instructions for further information if need be. If you have any questions or problems, do not hesitate to contact our Technical Hotline at: (800) 416-

8628 from 7:00 am to 5:00 pm, Monday through Friday, Pacific Standard Time or e-mail us at: edelbrock@edelbrock.com.

To check kit contents see exploded view of carburetor and parts description on last page. Verify that all parts underlined on list are in your kit.

Carb Kit contains all necessary parts and instructions to rebuild your Edelbrock Carburetor properly. When similar parts are contained in the Carb Kit, choose the ones that most closely match the existing parts. Some parts in the kit may not be needed.

1. DISASSEMBLE carburetor use accompanying exploded view as a guide..

➾Remove pump lever by driving roll pin through far enough to permit

release of lever.

➾Remove air horn screws. ➾Remove power piston by pressing down and releasing with a snap. ➾Remove power piston spring(s). ➾Do Not turn nor remove factory-adjusted stop screw next to power

piston. (APT) Adjustable part throttle.

➾Do Not turn nor remove factory-adjusted screw in aneroid cover. ➾Turn idle mixture needles clockwise and record number of turns

needed to lightly bottom them, for use during reassembly. Remove needles.

➾Disassemble choke cap from housing per Figure 13 (not applicable

to remote choke models).

2. CLEAN

carburetor.

➾Soak the carb parts (except as noted below) in a cold immersion

type carb cleaner.

➾Use mineral spirits or kerosene to clean solenoids, choke cover,

aneroid, float, float bowl inserts, vacuum breaks, seals or other parts containing rubber. Do not immerse these parts in carb cleaner.

➾Blowout all passages with compressed air . ➾After a thorough cleaning of all castings and parts, pay particular

attention to the cleanliness of the power piston and the body casting bore where it is housed. Any sticking of the power valve will prevent proper fuel control and affect driveability.

3. REASSEMBLE

carburetor and ADJUST following sequence illustrated.

➾Refer to model number for specifications. Use figure 1 to find

position of model number

➾Install new intermediate choke shaft seal in float bowl. Lip faces

outward. On Hot Air Choke models, install additional shaft seal in

choke housing. Lip faces float bowl. Disregard for remote choke models.

➾Do not install float needle pull clip into holes in float arm. ➾Install power piston. Press plastic retainer into bore until flush with

top of float bowl casting.

➾Carefully remove pump cup (with garter spring, if used) from pump

head. Install new cup (with new garter spring, if used) on pump head.

➾If used, install new pump stem seal and retainer in air horn. Lip

faces toward outside of carburetor. Lightly stake casting around retainer.

➾Select correct air horn gasket by matching replacement to old

gasket.

➾Tighten air horn screws in numerical sequence per illustration.

Torque screws 32-60 in-lbs.

➾Install the choke cover and

coil assembly per Figure15. Use the cover gasket on hot air model only (1903). Do not use the cover gasket on electric choke model 1904,05,06,10.

4. REINST

ALL

carburetor to intake manifold, torque mounting bolts to 110 in-Ibs.

5. ADJUST idle mixture and speed according to vehicle manufacturer's specifications.

FIG. 13

CHOKE

SETTINGS

PER

NOTCH

PER

NOTCH

PER

NOTCH

PER

NOTCH

PER

NOTCH

CARB #

1901

(8904S)

1902

(8905S)

1903

(8906S)

1904 1905 1906

(8907S)

1910

(8908S)

FIG. 4

AIR

VALVE

SPRING

7/8 TURN

1 TURN

FIG. 5

CHOKE

COIL

LEVER

1/8”

FIG. 6

FAST

IDLER

48°

FIG. 7

VACUUM

BREAK

22°

27°

FIG. 9

UN-

LOADER

40°

FIG. 2

PUMP SETTINGS LEVER DIM. HOLE

INNER

13/32”

5/8”

ADJUSTMENT SPECIFICATIONS

Page 2 of 4

Rev. 10/02

ALUMINUM TAG

WITH EDELBROCK’S

MODEL NUMBER.

MANUFACTURER’S NUMBER.

PRESS DOWN GENTLY ON FLOAT TANG UNTIL SEATED ON NEEDLE.

HOLD FLOAT HINGE PIN FIRMLY IN PLACE.

TO ADJUST, BEND FLOAT UP OR DOWN.

INSTALL PUMP ROD IN PROPER HOLE.

VENT VALVE COVER AND SPRING

REMOVED, CHOKE OPEN POSITION,

FAST IDLE CAM FREE.

TO ADJUST, REMOVE PLUG AND

TURN HEX SCREW. REPLACE PLUG

AFTER ADJUSTMENT.

PLACE .075” GAUGE BETWEEN IDLE STOP SCREW AND THROTTLE LEVER TANG.

GAUGE IN PLACE, VENT VALVE SHOULD BE CLOSED, GAUGE REMOVED, VENT VALVE SHOULD BE OPEN.

BACK OUT THROTTLE STOP SCREW. THROTTLE VALVES COMPLETELY CLOSED. TURN THROTTLE STOP SCREW IN UNTIL IT CONTACTS TANG ON THROTTLE LEVER. THEN TURN SCREW IN 1 1/2 TURNS.

TO ADJUST BEND ROD.

PUSH UP ON CHOKE COIL LEVER UNTIL CHOKE VALVE IS CLOSED.

INSERT .120” GAUGE IN HOLE. LOWER EDGE OF LEVER SHOULD JUST TOUCH GAUGE.

TO ADJUST SUPPORT PUMP LEVER ON PUMP END AND BEND LEVER ON PUMP ROD SIDE.

BACK OUT THROTTLE STOP SCREW THROTTLE VALVES HELD CLOSED.

TO ADJUST LOOSEN ALLEN LOCK SCREW. AIR VALVE HELD CLOSED. TURN ADJUSTING SCREW

CLOCKWISE UNTIL TORSION SPRING CONTACTS PIN ON AIR VALVE SHAFT. THEN TURN

ADDITIONAL SPECIFIED TURNS AND TIGHTEN ALLEN LOCK SCREW.

(ADJUSTMENT SPECIFICATIONS TABLE)

CAUTION: PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REMAIN IN SAME POSITION WHEN GAUGE IS USED.

1. ROTATE DEGREE SCALE UNTIL ( 0 ) IS OPPOSITE POINTER

2. CHOKE VALVE HELD COMPLETELY CLOSED. PLACE MAGNET SQUARELY ON TOP OF CHOKE VALVE.

3. ROTATE BUBBLE UNTIL IT IS CENTERED.

4. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUSTMENT IS OPPOSITE POINTER.

5. FOLLOW NUMERICAL OUTLINE IN MAKING ADJUSTMENT, INSTEAD OF MEASURING GAP AT EDGE OF CHOKE VALVE. MAKE ADJUSTMENT TO BRING BUBBLE BACK TO CENTER POSITION.

GAUGE: J-26701 KENT MOORE TOOL

BT-7704 BORROUGHS TOOL

PLACE CAM FOLLOWER ON SECOND STEP OF FAST IDLE CAM NEXT TO HIGH STEP.

TO ADJUST, BEND TANG ON FAST IDLE CAM

FOLLOW GAUGE SET PROCEDURE FIG.7

PUSH UPWARD ON CHOKE COIL LEVER, MOVING CHOKE TOWARD CLOSED POSITION UNTIL STOP IS MADE.

( BUBBLE ON ANGLE GAUGE SHOULD BE CENTERED.)

SPRING ADJUSTING SCREW.

AIR VALVE SHAFT.

ALLEN LOCK SCREW.

MEASURE FROM TOP OF CHOKE VALVE WALL TO TOP OF PUMP STEM.

INNER.

OUTER.

BOWL COVER GASKET REMOVED MEASURE FROM TOP OF CASTING TO TOP OF FLOAT 3/16” IN FROM TOE OF FLOAT.

CAUTION : DO NOT EXERT PRESSURE ON RESILIENT NEEDLE VALVE.

DRY FLOAT LEVEL ADJUSTMENT

CARBERUTOR IDENTIFICATION

ACCEL. PUMP ROD ADJUSTMENT

AIR VALVE SPRING ADJUSTMENT

ANGLE GAUGE METHOD

FAST IDLE CAM (CHOKE ROD) ADJUSTMENT

BOWL VENT VALVE ADJUSTMENT

CHOKE COIL LEVER ADJUSTMENT

Fig. 2

Fig. 1

Fig. 3

Fig. 5

Fig. 7

Fig. 8

Fig. 4

Fig. 6

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