Rochester Carburetors

OLDSMOBILE -1949-50 AUTOMATIC CHOKE CARBURETORS

7001570 (1949) - 7002570 (1950) - Use 7002570 As Replacement

BULLETIN 9 C-500 Dote 4-1-53

Supersedes Bulletin 9A-103 Dated !-1-51, and

Group I Dated 1-1-49, Group Ill Dated 1!-1-49

For Both Models

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COVER

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-----------·---------- ---------------------·---·-------------------------------

BOWL FLOAT ASSEMBLY

OUTER

HOUSING

ASSEMBLY

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62

51 60 i fa

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24

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36~ a 16

15() ® 14

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56 o0

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52

" 40p

------------ ---------------------------------------- - ----------------THROTTLE

BODY

ASSEMBLY 45

39

i 33' 21 ' 34 ' w 55

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PARTS SHOWN ARE FOR IDENTIFICATION ONLY . CONSULT PARTS LIST FOR CORRECT PART NAME ANO NUMBER.

REPAIR KIT-7001353 (7001570) - 7001376 (7002570) GASKET KIT - 7001849 Carburetor Carburetor

COMMON PARTS Illu s. No. Part No. Part Name Illus_ No. Part No. Part Name

1 342139 Strainer-Fuel Inlet 26 7001643 Valve-Choke 444571 Plug- I/a" Dryseal N.P.T.F. 27 7001647 Retainer-Stat Cover- Toothed 555702 Gasket-Flange 28 7001649 Retainer-Stat Cover-Plain

2 1875051 Screw-Trip Lever Attaching 29 7001650 Choke Counterweight and Collar Assy. 3 1875069 Pin-Choke Piston 30 7001652 Trip Lever-Choke

1875256 Rivet P lu~Passage 31 7001653 Pump Actuating Shaft Assy. 4 1875354 Washer- pacing 32 7001656 Packing-Pump Actuating Shaft 5 7000006 Pin-Cotter 33 7001664 Screw-Fast Idle 6 7000745 Screw-Cover Attaching 34 7001669 Needle-Idle Ad justing 7 700074 7 Screw-Pump Attaching 35 7001671 Cam -Fast Idle 8 7001 494 Tube-Idle 36 7001674 Valve-Pump Discharge 9 7001572 Cover A ssembly 37 7001676 Gasket-Cover

7001 5 74 Ball-Plug o/.n" Dia . · 38 7001677 Gasket-Th rattle Body 10 7001576 Power Valve Actuating Assy . 39 7001678 Screw-Throttle Body Attaching 1 l 7001586 Float A ssy. 40 7001679 Rod-Choke 12 7001595 Pin-Float Hinge 41 7001687 Felt-Large 13 7001597 Gask~t-Strainer Nut 42 7001688 Felt-Small 14 7001604 Strainer-Pump Inlet 43 7001689 Washer 15 7001605 Reta iner-Pump Inlet Strainer 44 7001690 Spring-Fast Idle and Idle Stop Screws 16 7001606 Plug-Pump Fill Hole 7001699 Plug-Expansion, Choke 17 7001498 Jet-Main Metering (lean) 45 7001844 Throttle Bod$' A ssy. 17 7001607 Jet-Main Metering (Std.) 46 7001846 Float Valve, eat and Gasket Assy . 18 7001608 Power Valve As'fj.. 7001849 Gasket Kit 19 7001613 Gasket- Power alve 47 7001850 Float Balance, Spring and Clips 20 7001614 Pump Fill Check Valve Assy. 48 7001851 N ut-Strainer 21 7001619 Screw-Idle Stop 49 7001852 Pump Shaft Assy . 22 7001632 Spring- Pump Actuating 50 7002305 Screw-Choke Valve Attaching 23 7001633 51 7002520 Float Bowl Assy. Spring-Pump Diaphragm 24 7001.635 · Outer Housing Assy . 52 7002760 Gasket-Stat Cover

7001637 Ball- Plug ~" Dia _ 53 7002771 Stat Cover and Coil Assy. 7001638 Ball-Plug ~4'' Dia _

25 7001640 Choke Shaft Assy _

Carburetor Pump Pump Lever-Assembly Housing Actuating-

No. Assembly Outside 56 57 58

7001 6 70 7001616 7001617 7001657 7002 5 70 7002522 7002523 7002530

54 7003190 Spring-Idle Ad justing Needle 55 7003561 Screw- Fast Idle Cam Attaching

PARTS WHICH DIFFER

Tube-Piston- Main Rod-Choke Well Pump

59 60 61

7001658 7001675 7001680 7002529 7002124 7002531

Cover and Bowl

Assembly 62

7001843 7002565

Pump Rack and

Diaphragm Assembly

63

7001847 7002566

Repair Kit

7001353 7001376

Tube­Bowl Vent

7001673

OLDSMOBILE-1949-50 Automatic Choke Carburetors 7001570 (1949) - 7002570 (1950)

CARBURETOR ADJUSTMENTS Make adiustments in following order-

FLOAT ADJUSTMENT

With cover gasket ren1ovcd and cover held upside down,

carefully bend float as shown to obtain a scale dimension

23;)2'' from face of cover to top of soldered seam at front

of floa t. DO NOT BEND AT FRONT OF FLOAT.

FLOAT TENSION ADJUSTMENT

To insure proper fuel level and sufficient entry of fuel

into bowl under high speed operation the float tension

adjustment must be made as follows: bend float tang

against balance spring to lessen drop and away from

spring to increase drop. Tension is correct when botton1

of float is 1j8 " above power diaphragm stem, when float

is suspended freely from cover.

PUMP LEVER ADJUSTMENT

With pump rod in recommended outside hole for 1949

A1odels o r center hole for 1950 Models back off idle stop

screw and fast idle screw so that throttle valves are full

closed. Remove pump rod from throttle lever and pull

down to full allowable cocked diaphragm position. With

pump rod directly under its hole in throttle lever carefully

bend rod so that top edge of pump rod is flush with

bottom edge of hole in the throttle lever. Reassemble

pump rod to throttle lever. This insures correct pump

delivery at all speeds.

PUMP TARGETING ADJUSTMENT

For 1949 Models-Although the actual point of dis­

charge cannot be seen, it can be checked. With fuel in the

carburetor actuate thro ttle lever slowly and note pump

discharge by looking into the air horn. The pump dis­

cl1arge must appear as a fan shaped spray. Only a very

slight bend is necessary to properly target the pump jets .

PUMP DISCHARGE MUS1' NOT SPRAY OUT OF

AIR HORN.

- -·-' ."' ~"'--·-·

• ~ • •

FLOAT ADJUSTMENT

FLOAT TENSION ADJUSTMENT

PUMP ADJUSTMENT

A

1949 MODELS

I

OLDSMOBILE-1949-50 Automatic Choke Carburetors 7001570 (1949) - 7002570 (1950)

CARBURETOR ADJUSTMENTS, Cont'd.

For 1950 Models-With small quantity of fuel in car­buretor, carefully bend pump jets to target against their respective pump splashers as shown to give a fan-shaped spray.

CHOKE ROD ADJUSTMENT

With thermostat' cover set at index turn fast idle screw until it contacts the first or intermediate stop of fast idle cam. Be sure choke trip lever is in contact with choke counterweight. Choke valve will now be slightly open. With fast idle screw and fast idle cam held in this position,

. carefully bend choke rod to obtain a clearance of .147'' between bottom edge of choke valve and small inside diameter of air horn. No. 26 drill is .147''. Note: Choke Rod must not rub side of housing at any choke valve

• • pos1t1on. Note: Fast idle cam ta11g n1ust not rest upon choke rod

when choke valve is fully closed. If necessary, bend fast idle cam tang slightly so that choke va,lve may fully close.

UNLOADER ADJUSTMENT

Thermostat cover set at index. Open throttle leV'Cr to full wide open position. Be sure choke trip lever is in contact with choke counterweight tang. Hold throttle lever in this position and carefully bend tang of throttle lever to obtain a clearance of .238'' for 1949 Atodets or .220'' for 1950 Models between bottom edge of choke valve and small inside diameter of air horn.

FAST IDLE ADJUSTMENT

With thermostat cover set at index move fast idle cam so that choke valve is full closed. Hold throttle lever in closed ·position so that fast idle screw rests on high step of fast idle cam. Now adjust fast idle screw to obtain a clear­ance of .023 between throttle valves and bore of throttle body on side opposite idle screws.

Note: If making this adjustment on engine having engine and transmission hot. Hold the throttle partially open and rotate fast idle cam so that the fast idle screw rests 100 7c on lowest point of the low step of cam.

With screw and cam in this position, adjust screw to give an engine speed of 500 RPM.

This adjustment assures proper idle for starting the engine and should always be checked in the event stalling is experienced during the warm·up period.

(arb11relor Ga_11!!,e 81'-17 (For 1949 Models) and 81._35 (1.-or 1950 Models.) and Bending Tool BT-18 are at•ailable from Borroughs Tool Co., Kalamazoo, Michi!!,an.

1950 MODELS PUMP TARGETING ADJUSTMENT

.!"AST IDL£ CAM AGA!~"ST !!'AST 1DLB SCR!iW

OLDSMOBILE-1949-50 Automatic Choke Carburetors

Year and Model

1949-50 Olds "8"

7001570 (1949) - 7002570 (1950)

TUNE-UP SPECIFICATIONS Spark Plug

Gap

.030"

Breaker Point Gap

. 015"

Ignition Timing

CARBURETOR SPECIFICATIONS Dimensions:

Primary Venturi- 1.187"

Secondary Venturi-.343"

Identification:

Main Metering Jets-Stamped 54

Idle Discharge Holes:

Idle Needle Orif iGe-.052''

Second Id le Hol~-.040" x Flush

Third Idle Hole-.036" x .050" Above

Spark Drilling-.040" x .010" Nick

Pump Jet-.026" (1570)

.024" (2570)

Choke Restriction-.076"

Idle Tube Restriction-.025"

Power Restriction-.033"

Idling RPM

375 (DR)

A GENERAL MOTORS PRODUCT c MOTORS PllODOCTS A UNITED MOTORS-AC LINE

UNITED MOTORS SERVICE-AC DIVISION, GENERAL MOTORS PRODUCTS .._.........OF CANADA LIMITED, OSHAWA, ONTARIO

•

AIR HORN ASSEMBLY 68

Rochester Carburetors

OLDSMOBILE -1951 BULLETIN 9 C-501

Date 2-15-53 Supersedes Bulletin 9A-10-4

Dated 2-1-51 and Group '4 Dated 1-1-51

AUTOMATIC CHOKE CARBURETOR - 7002900

34 42 JJ 44

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-------------------------------------------------- (I)2J

FLOAT BOWL

ASSEMBLY

I 65

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SS

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G Zl!IUM mm 27 67 60

-----------------------------------------------~ 36 20

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52 0 54 ASSEMBlY 53 I 0 0 I

38 0 I •• I "" -64 24 I

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60

45

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PARTS SHOWN ARE FOR IDENTIFICATION ONLY. CONSULT PARTS LIST FOR CORRECT PART NAME AND NUMBER.

16

JO

S6

REPAIR KIT-7001390 GASKET KIT-7001 393

Il lus. No. Part No.

1 2 3 4 5 6 7 8 9

10 1 1 12 13 14 15

16 17 18 19 20

21 22 23 24

25

26 27 28 29 30 31

114627 131958 435864 837527

1875051 1875069 1875343 1875354 1887572 7000006 7001125 7001126 7001128 7001388 7001389 7001390 7001393 7001394 7-001395 7001595 7001597 7001619 7001637 7001647 7001649 7001.658 7001669 7001699 7001850 7002055 7002101 7002117 7002120 7002305 7002760 7002806 7002814

PARTS LIST Part Name

Nut-Choke Suction Tube Screw-Stat Cover Attach ing Cotter Pin-Fulcrum Lever Retainer-Check Valve Screw-Choke Trip Lever Pin-Choke Piston Screw-Cam Attaching Washer-Spacing Washer-Fulcrum Lever Stud Cotter Pin-Choke and Pump Rod Plug-Power Valve Spring-Power Valve Piston-Power Throttle Body Assy. Float Bowl Assy. Repair Kit Gasket Kit Stat Cover and Coil A ssy. Float Va lve, Seat and Gasket Assy. Pin-Float Hinge Gasket-Strainer Nut Screw-Idle Stop Ball-Plug ~" Dia . Reta iner-Stat Cover-Toothed Reta iner-Stat Cover-Plain Piston-Choke Needle-Idle Adjusting Plug-Expansion-Choke Float Balance Sprin·g and Clips Plug-Idle Passage Spring-Pump Return Ball-Pump Discharge Ball-Pump Inlet Check Screw-Choke Va lve Gasket-Stat Cover Float Pull Clip Plug-Lead Ball .17" Dia.

Illus. No. Part No.

32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

7002841 7002842 1002862 7002866 7002883 7002896 7002902 7002906 7002951 7003076 7003082 7003083 7003088 7003092 7003094 7003095 7003097 7003098 7003111 7003122 7003123 7003126 70031 27 7003128 7003129 7003130 7003132 7003139 7003140 7003144 7003147 7003189 7003190 7003242 7003582 7003700 7004452

Part Name --·-· -

Gasket-Choke Housing Screw-Choke Housing Attaching Nut-Strainer Strainer-Pump Inlet Packing-Choke Suction Tube Spring-Power Piston Choke Suction Tube Assy. Choke Housing Assy. Jet-Main Metering Main Well Support Assy. Gasket-Air Horn Strainer-Fuel Inlet Float Assy. Choke Sha ft Assy. Valve-Choke Choke Co~nterweight Lever-Choke Trip Pump Plunger Assy. Fulcrum Lever and Collar Assy. Screw-Cam Spring-Idle Stop Screw Carn-Fast Idle Gasket-Throttle Body Rod-Pump Rod-Choke Screw-Air Horn Attaching Screw-Venturi Cluster Attaching Screw-Throttle Body Attaching Piston-Pump Discharge Check Plate-Choke Baffle Boot-Pump Plunger Venturi Cluster Assy. Spring-Idle Adjusting Needle Clip-Rod End Va lve-Pump Discharge Check Spring-Pump Discharge Ball Air Horn Assy.

OLDSMOBILE -1951 Automatic Choke Carburetor 7002900

CARBURETOR ADJUSTMENTS Make adiustments in following order-

FLOAT LEVEL ADJUSTMENT This adjustment is made with air horn gasket in

position and air horn inverted on flat surface. (Figure 1.)

1. Carefully bend float arms vertically until floats appear level in relation to each other.

2. Place Float Gauge in position as shown, with locating tangs inserted into the secondary venturii

• • to position gauge. 3. Bend float button, which contacts the float

needle, until the floats touch the top portion of the gauge.

4. Now bend arms horizontally until each float is centered between the gauge legs. Tilt Air Horn assembly 90° each side and check that floats do not touch gauge legs. This insures the floats will not rub sides of float bowl.

FLOAT DROP ADJUSTMENT To insure proper fuel level lnd sufficient entry of

fuel into the bowl under high speed operation the float drop adjustment must be made as follows: (Figure 2.) bend the float tang, at the rear of the float, against the balance spring to lessen the drop and away from the balance spring to increase the drop. The tension is correct when the distance from the bottom of the air horn gasket to the bottom of the floats, with the air horn assembly held in an upright position, is equivalent to the scaled dimen­sion as shown (1%'').

PUMP ROD ADJUSTMENT Back off the idle stop screw and the fast idle screw

so that the throttle valves are fully closed. (Figure 3.) Remove pump rod from rocker arm and hold rocker arm down so that the pump plunger is in its extreme "up" position. With pump rod directly over the rocker arm hole carefully bend the pump rod until the bottom edge of the pump rod is flush with the top edge of the rocker arm hole. Reassemble pump rod to rocker arm. This insures correct pump delivery at all speeds.

Float Should Toucn Top of Gouge

Float Gauge

Floats Should Be Equi-Dislc1nt

f from l egs of G ouge I

0

> • •

FIGURE 1

FIGURE 2

Bottom Edge of Rod Even ,witb--....,,

~I T~p ol Hole .;·~

FIGURE 3

\ l

•

OLDSMOBILE -1951 Automatic Choke Carburetor 7002900

CARBURETOR ADJUSTMENTS, Cont'd.

CHOKE ROD ADJUSTMENT With thermostat cover set at index turn fast idle

screw until it contacts the intermediate or middle

step on the fast idle cam. Be sure choke trip lever

is in contact with choke counter-weight. Choke valve

will now be slightly open. With fast idle screw and

fast idle cam held in this position, carefully bend

the choke rod to obtain a clearance of .177'' between

bottom edge of choke valve and flat on inside diam­

eter of air horn. (Figure 4.)

Note: Choke Rod must not rub side of housing at

any choke valve position.

UNLOADER ADJUSTMENT With thermostat cover set at index and choke trip

lever in contact with choke counter weight, move

throttle to full open position. Hold throttle lever

in this position and carefully bend tang of throttle

lever to obtain a clearance of .209'' between bottom

edge of choke valve and flat on inside diameter of air

horn. (Figure 5.)

FAST IDLE ADJUSTMENT With thermostat cover set at index move fast idle

cam so that choke valve is fully closed. Hold throttle

lever in closed position so that fast idle screw rests

on high step of fast idle cam. Now adjust fast idle screw to obtain a clearance of .026'' between throttle

valves and bore of throttle body on side opposite idle screws. (Figure 6.)

Note: In making this adjustment on engine have

engine and transmission hot. Hold the throttle par­

tially open and rotate fast idle cam so that the fast

idle screw rests on the lowest point of the low step

of cam. With screw and cam in this position, adjust

screw to give an engine speed of 500 R.P.M.

This adjustment assures proper idle for starting

the engine and should always be checked in the event

stalling is experienced during the warm-up period.

Bending Tool BT-18, Combination Carb11retor Gauge BT-49, Float Gartge BT-51, and Suction Tube Tool BT-45 are available from Borroughs Tool Co., Kalamazoo, Michigan.

FIGURE 4

Use La rge End of 6 Com bination Gauge

• ,,._ Throttle Lever

Ful l Open

FIGURE 5

FIGURE 6

OLDSMOBILE -1951 Automatic Choke Carburetor 7002900

Year and Model

1951 Olds " 8"·

TUNE-UP SPECIFICATIONS Spark Plug

Gap

.030"

Breaker Point Gap

.015"

Ignition Timing

2Y2 BTDC

CARBURETOR SPECIFICATIONS Dimensions:

Primary Venturi-1 .062"

Secondary Venturi-.562"

Identification:

Main Metering Jet-Stamped 51

Air Ho.rn Gasket-Stamped 3082

Idle Discharge Holes:

Idle Needle Orifice-.0625"

Second Idle Hole-.031" x .002" Nick

Third Idle Hole- 025" x .053" Above

Fourth Idle Hole-.025" x .086" Above

Spark Drilling-.040" x .015" Nick

Pump Discharge Hole-.031"

Choke Restriction-.076"

Power Restriction-.05.4"

Idling RPM

375 (DR)

A GENERAL MOTORS PRODUCT A UNITED MOTORS-AC LINE

UNITED MOTORS SERVICE-AC DIVISION, GENERAL MOTORS PRODUCTS...__ Of CANADA LIM ITED, OSHAWA, ONTARIO

- -GM , ..... ••'ll•• UM S PARTS

• • ~SALES Rochester Carburetors

MODEL 4GC

1952-1953 OLDSMOBILE

BULLETIN 9C-502 PAGE 1 OF 4 DATE: MAY I 1960

REPLACES: • UNllED llDTOAS SYSTEM - -

6 2 '

' : f ,

(

AIR HORN PARTS

11 ~

14

i I 16

15

i 19

0 20

9C-502 AND 9C-503 2 / 15/ 53

·~

17 , r I

l

D 21

18

·--·-------- ---- - - -- - - - - -~ -- - - -- - -- - - - -- ---- - - - ----- -- --I ~-~

:39 ~ I ~ '

I 40 49

CJ G 4 2

23 l? g 26

24 I (2 27 ~

32 33

25 • 22 ~ ~ ~ .,;.: 28 0 30 ~

I ~ ';' 37 : er ~ @ ~ 35

52 UJ

~ 0 53 ""

v...; 57

45 46 47 48 • 54 © 38 '1 l 0 § 50 v i.:5" 29@

'§ 58

51 ~ : CHOKE PARTS 56

59 29A «) FLOAT BOWL PARTS

- - - - ~1 i -, ~3-; ;: -;1~ - - - -7-; :- - -;-8 «_l - - ~ - - - -- ;= -~---- - - - - - - - - -60 •<> • · 7211\>' 0 o • o o 0 ~ f

• ~ , 62 Q Q 0 0 0 0 • 90 DO ~ 69 73 ltnt@llt <) Y o? 79 n 8~ 0 0 :

. 6"0 (~~:f' 66 :::: ee 0 80 &.. 84 " 8~ 0 (~ ~Jo : 89

6®»5 $'.-0<) I - 7 6 o 81-S <E) ~ 88 I THROTTLE

RETURN CH ECK c;7~ 86 87 I THROTTLE BODY PARTS 7 o I

PARTS SHOWN ARE FOR IDENTI Fl CATI O N ONLY. CONSULT PARTS LIST FOR CO RRECT PART NAME AND NUMBER

-1952 1952 1953 1953 1953 YEAR

Hydramatic Synchromesh Hydramatic Synchromesh Dynaflow APPLICATION

7004300 7004800 7005600 7005700 7006250 CARBURETOR No. 7005600 7005700 7005600 7005700 7005600 REPLACEMENT PACKAGE 7009316 700931 6 7009317 7009317 70093 17 MASTER REPAIR KIT

FR-500 FR-500 FR-500 FR-500 FR-500 OFF KAR KIT . FR-57 FR-57 FR-57 FR-57 FR-57 KLEANOUT KIT

7009291 7009291 7009291 7009291 7009291 GASKET KIT

Illus. AIR HORN PARTS No.

1 7006061 7006061 7006061 7006061 7006061 *Gaske t - Air Horn 2 7000349 7000249 7000249 7000249 7000249 Screw - Air Horn 3 7004527 7004527 7004527 7004527 7004527 Valve - Idle Vent 4 7004528 7004528 7004528 7004528 7004528 Guide - Idle Vent 5 7004529 7004529 7004529 7004529 7004529 Sorinq - Idle Vent 6 7007617 70076 17 7007617 7007617 7007617 Pump Shaft a nd l eve r Assembly 7 7007616 7007616 7007616 7007616 7007616 *Clio - Pumo Sha f t 8 7005032 7005032 7005032 7005032 7005032 *Clio - Pumo Plunaer 9 7003147 7003147 70031 47 7003147 7003147 *Boot - Pumo Plunaer

10 7005537 7005537 7005537 7005537 7005537 * Pump A ssemblv 1 1 7002862 7002862 7002862 7002862 7002862 Stra iner N ut 1 2 7003083 7003083 7003083 7003083 7003083 *Strainer - Fuel Inlet 13 7001597 7001597 7001597 7001597 7001597 *Gasket - Strainer N ut 14 7005589 7005589 7005589 7005589 7005589 A ir Horn Assemblv 15 7004302 7004302 7004302 7004302 7004302 Power Pisto n A ssembly 16 7002897 7002897 7002897 7002897 7002897 Sorina - Power Piston 17 7000199 7000199 7000199 7000199. 7000199 Float Assembly 1 8 7001595 7001595 7001595 7001595 7001595 Pin - Float Hinne 19 7004682 7004682 7004682 7004682 7004682 *Needle and Seat Assembly 20 700 1613 700161 3 7001613 700 1613 7001613 *Gasket - Needle Seat 21 7006079 7006079 7006079 7006079 7006079 *Strainer - Needle Seal

No.

* MASTER REPAIR KIT CONTENTS PRINTED IN CANADA.

BULLETLN 9C-502 PAGE 2 OF 4

1952 Hydramatic

7004300 Illus. No.

22 7004597 23 -24 -- 25 -26 7001674 27 7004587 ---28 7002120 - ·--29 - 7001604

29A 7001605 - -- --30 7005286 -·---·- ---31 7004681 ----- ... ·- ·--32 700431 7 - --33 700431 1 - --- -34 451910 --- --35 - 7Q07_803 36 700265 1 --- - I-

_ _]6 7002661 .... ·-37 7001608 - - -38 700 1613 -

39 7007502 --·~

40 -·--· 7004277 4 1 700482 1 - ---·· - -----42 7004285 . 43 7002760 --44 7004684 45 ,,_ - - 187505 1 46 7003097 - -47 1875354

1952 Synchromesh

7004800

7004597 ---

7001674 7004587 7002120 7001604 7001605 -7005286 -----7004681 . ·--7004317 -7004847

451910 -·-·

7007803 . 7002651 7002643 7001608 7001613

7007502 7004277 7004821 7004285 --7002760 7004684 - ... 1875051 . - - · · 7003097 1875354 - . --

41L. 7004286 7004286 49 7004284 7004284 . -50 7007627 7007627 ·-·-- --· 5 1 700428 1 7004281 --··· 52 7001658 7001658 -53 1875069 1875069 -· - -- . ·- -- . 54 700 16 37 7001637 -·- - ·- -55 7002814 7002814 -----56 7003135 7003135 57 7001647 7001647 ·--58 7001649 7001649 59 701042 4 7010424

60 7006887 7006887 61 7004324 7004324 62 7005188 7005188 63 121744 121744 -64 7004395 7004395 65 700356 1 700356 1 66 7004326 7004326 67 7005109 7005109 68 7003137 7003137 69 7004325 7004325 70 7003137 7003137 71 7011546 7011546 72 7003176 7003176 73 700161 9 7001619 74 7003176 7003176 75 700440 2 7004402 76 7003 190 1003190 77 7004683 7004683 78 7004397 7004397 79 7004399 7004399 80 7004398 7004398 81 7005145 7005145 82 7004396 7004396 83 700440 1 7004401 84 7002287 7002287 85 7005 109 7005109 86 1875066 1875066 87 7010435 7010435 88 56 1409 561409

89 90

1953 1953 1953 YEAR . -

Hydramatic Synchromesh Dynaflow APPLICATION

7005600 7005700 7006250 CARBURETOR No. FLOAT BOWL PARTS

7004597 7004597 7004597 *Sprina - Pumo Return 7003838 7003838 7003838 *Guide - Pumo Discharne 7002118 7002118 7002118 *Sprinn - Pumn Discharne 7002117 70021 17 70021 17 *Ball - Pumo Discharae

- - - *Valve - Pumo Discharae - - - *Pu mo Ven t Check Valve Assembly - -

7002120 7002120 7002120 *Ball - Pumn Inlet 7001604 7001604 7001604 *Strainer - Pumn Inlet 7001605 7001605 7001605 .. *Retainer - Pu mo Stra iner 7005286 7005286 7005286 Siaht Plua .7005590 7005590 7005590 Float Bowl Assembly -7005533 7005533 7005533 Venturi Cluster - Primarv 7005534 7005719 7005534 Venturi Cluster - Secondary

451910 451910 451910 Screw - Cluster Attachinn 7007803 7007803 7007803 *Gasket - Venturi Cluster 7002649 7002651 7002649 Jet - Primary · 7002656 7002647 7002656 Jet - Secondarv 7001608 7001608 7001608 *Power Valve Assembly 7001613 7001613 7001613 *Gasket - Power Valve

CHOKE PARTS

7007502 7007502 7007502 *Gasket - Choke Housina ·-- 7004277 7004277 7004277 Choke Housinn Asscmblv 7004821 7004821 7004821 Screw - Choke Housina 7004285 7004285 7004285 Baffle Plate 7002760 700.2760 7002760 *Gasket - Stat Cover 7004684 7004684

- ·-· 7004684 Stat Cover. Coil and Gasket Assemblv

187505 1 1875051 1875051 Screw - Trio lever 7003097 7003097 7003097

. Tri,:, lever --·-1875354 1875354 1875354 Washer - Snac inn

7004286 7004286 7004286 Choke lever and Choke Assemblv 7004284 7004284 7004284 Choke Va lve 7007627 7007627 7007627 Screw - Choke Valve 7004281 7004281 7004281 Choke Shaft and lever Assemblv . 7001658 7001658 7001 '658 Choke Piston J 1875069 1875069 1875069 Pin - Choke Piston 7001637 7001637 7001637 Plun - Lead Ball - Larae 7002814 7002814 7002814 Plun - lead Boll - Small 7003135 7003135 7003135 Plug - Expansion 7001647 7001647 7001647 Retainer - Stat Cover - Toothed 7001649 7001649 7001649 Retainer - Stat Cover - Plain -7010424 7010424 7010424 Screw - Stat Cover

THROTTLE BODY PARTS

7006887 7006887 7006887 *Gasket - Throttle Bodv 7004324 7004324 7004324 Screw - Throttle Bod:i: - Large 7005 188 7005188 7005188 Screw - Throttle BodY - Small

1 21744 1 21744 1 21744 lockwasher - Small Screws 7004395 7004395 7004395 Cam - Fast Idle 7003561 700356 1 7003561 Screw - Cam Attach inn 7004326 7004326 '7004326 Choke Rod 7005109 7005109 7005109 *Clin - Choke Rod 7003137 7003137 7003137 *Clin - Pumn Rod - Upper -7004325 7004325 7004325 Pumn Rod 7003137 7003137 7003137 *Clin - Pumn Rod - lower 7011546 7011546 7011546 Fast Idle Screw 7003176 7003176 7003176 Snrinn - Fast Idle Screw 7001619 7001619 7001619 Id le Stoo Screw 7003176 7003176 7003176 Snrinn - Idle Ston Screw 7004402 7004402 7004402 *Idle Needle 7003190 7003190 7003190 Snrinn - Idle Needle 7005591 7005591 7005591 Throttle Bodv Assemblv 7004397 7004397 7004397 lever - Secondary Act uotinn 7004399 7004399 7004399 Screw - Shaft Override Sorina 7004398 7004398 7004398 Serina - Shaft Override . 7005145 7005145 7005145 Snrinn - Secondarv Th rottle Return 7004396 7004396 7004396 Secondary lever

.

7004401 7004401 7004401 link - Secondary lever 7002287 7002287 7002287 Wosher - Secondarv Lever Link 7005109 7005109 7005109 *Clio - Secondarv Lever Link 1875066 1875066 1875066 Wosher - Secondorv Lever 7010435 7010435 7010435 Screw - Secondary Lever

561409 561409 561409 *Flange Gasket

THROTILE RETURN CHECK PARTS

7006214 Throttle Return Check Assembly 7006308 Contact Screw

* MASTER REPAIR KIT CONTENTS

·-

- -. ~,~ U·M·S ~

Rochester Carburetors MODEL 4GC

BULLETIN 9C-502 PAGE 3 OF 4 DATE: MAY, 1960 .

UllUO MOTORS SYSUM - - 1952, 1953 OLDSMOBILE ADJUSTMENTS AND SPECIFICATIONS

, GAUGE SHOULD JUST TOUCH FLOAT AT

HIGHEST POINT

BETWEEN GAUGE LEGS

FLOAT LEVEL ADJUSTMENT

1952 SETTING 1-3/ 8" GAUGE BT-66 1953 SETTING 1-9/ 16" GAUGE BT-87

W ith air horn gasket in place, position gauge over floats and against curv ature in air horn bore. Bend float arms at rear o f assembly so floats just touch g.auge, then bend float arms hor izontally to center each pontoon between gauge legs. Repeat on opposite Boats.

2 BENO FLOAT TANG TO ADJUST

FOR PROPER SETTING

~-~

. '~- ' .: v ·~~'""

'-.. MEASURE 2 114" FROM

GASKET SURFACE TO

BOTTOM OF FLOAT

FLOAT DROP ADJUSTMENT

1952 SETTING 1- 15/ 16" USE SCALE 1953 SETTING 2- 1/ 4" USE SCALE

Bend the float ta ng as requ ired to obta in correct distance fro1n thr gaskrt su rface to the bottom o f the float. with thr floa t h<tnging free. Note: 1952 floats use bala nce spring.

3

'

- I

BEND ROD TO ADJUST FOR

PROPER PUMP ROD SETTING

MEASURE FROM TOP OF

AIRHORN TO BOTTOM OF PUMP

PLUNGER SHAFT

THROTTLE VALVES COMPLETELY CLOSED

PUMP ROD ADJUSTMENT

SETTING 1-1/ 16" TOOL BT-18

With the fast idle and idle stop screws backed off and the throttle valves completely closed, bend the pump rod as shown to obtain the proper n1easure1nent fron1 the top of the air horn casting to the bottom of the pump plunger shaft.

4 BENO TANG TO

ADJUST FOR PROPER SETTING

"-----

- SPECIFIED GAUGE BETWEEN THROTTLE VALVE ANO BORE ON PfllMARY SIDE ,OPPOSITE

IDLE ADJUSTING NEEDLES

IDLE VENT ADJUSTMENT

SETTING .040" GAUGE BT-67 With the prirna ry throttle valves closed against a \\:ire gauge. bend the idle vent tang \Vith bending tool BT -69 so that the tang just touches the face of the valve \.\·hen in the closed position.

5 l

CHOKE MODIFIER ADJUSTMENT

SETTINC; IN D EX

With the throttle valves fully closed. loosen the center lock screw ( l ) and rota te the index pointer (2 ) counterclockwise until the choke valve closes and the pointer is positioned as above. Tighten the lock screv.r securely .

6

TURN FAST IDLE SCREW FOR PROPER SETTING

FAST IDLE SCREW ON HIGHEST STEP OF FAST IDLE CAM

GAUGE BETWEEN THROTTLE VALVE ANO BOl'tE, OPPOSITE IDLE ADJUSTING NEEDLES

FAST IDLE ADJUSTMENT

SETTING .020" GAUGE BT-67 Turn the fast idle sc rew against the high step of the fast idle cam until the spec ifi ed ga uge just fits betv..1een the throttle valve and bore. opposite the idle adjusting needles. This is a bench setting only, to provide a n initia l fast idle when the car is first started; when the engine reaches operating ten1perature. adjust the proper fast idle rpm with Cl tachon1eter. Fast idle set 1450 R.P.M. on high step of cam. transmission in neutral.

'

BULLETIN 9C-502 PAGE 4 OF 4

7 "' ll ---SPECIFIED GAUGE BETWEEN ~ UPPER EDGE OF CHOKE VALVE

AND DIVIDING WALL OF AIRHORN

~o

BEND ROD TO ADJUST FOR PROPER

CHOKE ROD SETTING

FAST IDLE SCREW ON SECOND STEP

AGAINST HIGH STEP

CHOKE ROD ADJUSTMENT

SETTING .053'' GAUGE BT-68

With the fast idle screw resting on the 2nd step <1nd <19a inst the high step of the fast idle ca1n. bend the choke rod as shown to obtain proper clearance betv..1ccn the choke valve edge .and the d ividing air horn 'vali. Use Tool BT-18.

8

THROTTLE VALVES WIDE OPEN

SPECIFIED GAUGE BETWEEN UPPER EDGE OF CHOKE VALVE I ANO DIVIDING WALL OF AIRHORN

BENO TANG TO ADJUST

UNLOADER ADJUSTMENT

SETTINC; .092" GAUGE BT-68

Bend th(• unlo<1der on the fa st idle earn to obtuin proper clearance betwf.'en the choke valve edge and the dividing ,1ir horn \.vall \.Vith the throttle valves wide opf.'n. Use Tool BT-69.

QUICK REFERENCE ADJUSTMENTS 7004300 7004800

ADJUSTMENT PRIM. SEC. GAUGE PRIM.

FLOAT LEVEL 1 -3/ 8 1-3/ 8 ST-66 1-9/ 16

FLOAT DROP 1-15 / 16 1- 15/ 16 SCALE 2- 1/ 4

PUMP ROD 1 - 1/ 16 - SCALE 1-1 / 16

IDLE VENT .040 - BT-67 .040

AUTO . CHOKE INDEX - - INDEX

FAST IDLE .020 - BT-67 .020

CHOKE ROD .053 - BT-68 .053

UNLOADER .09 2 - BT-68 .092

SEC. LOC K-OUT . 01 5 - FEELER .015

SEC. CONTOUR .035 - FEELER .035

9 CHOKE VALV E FULLY CLOS E INSERT FEELER GAUGE

BETWEEN LOCKOUT LEVER ~~? AND FAST IDLE CAM

~~ ,,_... • .;.._::.~::::: ~:.:.-o.-

IS BEND TANG TO

ADJUST FOR PROPER SETTING

ll!fJftl l I 'I' ' jf ' I •

SECONDARY LOCKOUT ADJUSTMENT

SETT INC; .015. USI'-: 1·00L R'f -91 W ith the choke (Ja/vc [11/l.11 closed. brnd thf.' lockout lever as sho\vn to obtain .0 15 cle;1rancc hct,vccn thf.' earn and the \vidcst surface of the lockou t lever at the point shown.

10 CHOKE VALVE WIDE OPEN

INSERT FEELER GAUGE BETWEEN LOCKOUT LEVER

AND FAST IDLE CAM

' I • ' • •

. / il.l/.ll/11' ·11,.rr .. ,,, ....

SECONDARY CONTOUR

SETTING .035" TOOL NO. BT-91 With th e choke "·alve held \Vide open and the f<.lst idle ea rn and secondary lcckout lever in position as sho,vn. there should be a c lea rance of .035" between the lever i.lnd ea rn.

Using bending tool BT-91 bend the lever tang to obtoin the pro per clf.'a rance.

-

7005600 7005700 TUNE-UP SPECIFICATIONS 7006250 SPARK PLUG GAP - .030"

SEC. GAUGE BREAKER POINT GAP - .016"

1-9/ 16 ST-87 CAM DWELL-26°-33°

2-1 / 4 SCALE IGNITION TIMING -- SCALE 1952 - 5 ° BTDC @ 800 R.P.M. - BT-67 1953 - 5 ° BTDC @ 850 RPM

- -IDLE R.P.M. -

- BT-67 1952 - SYN. 425 ( N)

- BT-68 HYD. 375 (DR) BT-68 . - 1952 SYN . 425 ( N) -

- FEELER HYO . 375 (DR)

- FEELER

NOTE: For complete ca'rburetor specifications, refer to 9D- 1 Section of the Parts and Service Manual.

Refer to Bulletin 90-9 for basic operation and overhaul procedures.

Amortca·• number ono o,.lglna.I e qvlpmont

iitl!li ca.rburot.ora

ROCHESIER ~~BURETORS M

...... t'""' -"''''""

-

AIR HORN PARTS

0

1

Rochester Carburetors MODEL 4GC

1954-1955-1956 OLDSMOBILE

fi\l 8

6

Q12

10

15

~ 17

BULLETIN 9C-504 PAGE 1 OF 5

DATE: 2-15-57 REPLACES:

9C-504, 5/15/55 9C-506, 12/15/54 9C-508, 11/1/55

--- - -- - - -- - -- -- - ~ - - -- --- - -- - -- --------- -- - - - - - - - - - - ..

FLOAT BOWL PARTS

@22 0 23 • 24 28

21 • 25 oa f 26

• J!, 27

38~ 39 iLJG~

41 43

33 I I

132 I

<a ~ I 30 v I

U'35 34 I

I ,--..

~ I :e. I

0 6), if.

I 36 37 31 I

I

45 48 ea49 <W 51

i @ ~ . 0 0 ' <;g;:>52 - -44 46 47 so ~ 53

I ' i L 0 •56 54 •

55 57

CHOKE HOUSING PARTS

------ - --- - - - ------ --- -- - - - ------ - -------- - -- ------59 60 61

i 0

0

63~ Qo

THROTTLE BODY PARTS

64

2ll 23 65 2lj

~

67

69 @1191119 0

. ~72

<r!QJ73

[~ M 68 74

• 76 0

0

0

0 81 THROTTLE RETU RN CHECK

0 87

PARTS SHOWN ARE FOR IDENTI FICAT ION ONLY. CONSULT PARTS LIST FOR CO RRECT PART NAME AND NUMBER

1954 1954-55 1955 1956 YEAR HYDRAMATIC SYNCROMESH HYDRAMATIC SYNCROMESH HYDRAMATIC APPLICATION

7005900 7006000 7007000 7007222 7007221 CARBURETOR No. 7005900 7006000 7007000 7009902 7009902 REPLACEMENT No.

-7009318 7009318 7009318 7009926 7009926 REPAIR KIT COMPLETE

7009292 7009292 7009292 7009946 7009946 GASKET KIT COMPLETE

7006 133 7006133 7006133 None None REPAIR KIT W / 0 GASKETS

7007134 7007134 .

7007134 None None GASKET KIT W / 0 FLANGE GASKET

Illus. AIR HORN PARTS No.

1 7006061 7006061 7006061 7006061 7006061 *Air Horn Gasket 2 7000249 7000249 7000249 7000249 7000249 Screw-Air Horn Attach ing 3 7004527 7004527 7004527 7004527 7004527 Idle Vent Valve 4 7004528 7004528 7004528 7004528 7004528 Idle Vent Valve Guide 5 7004529 7004529 7004529 7004529 7004529 Idle Vent Valve Serino 6 7007617 7007617 7007617 7007617 7007617 Pumo Shaft and Lever Assy. 7 7007616 7007616 7007616 7007616 7007616 *CIJo-Pumo Shaft 8 7005032 7005032 7005032 7005032 7005032 *Clio-· Pumo Plunaer 9 7006372 7006372 7006372 7006372 7006372 *Boot-Pumo Pluncer

10 7000208 7000208 7000208 7000208 7000208 * Pumo Assv. 1 1 7000262 7000262 7000262 7000262 7000262 Strainer Nut 12 7001597 7001597 7001597 7001597 7001597 *Gasket-Strainer Nut 13 7003083 7003083 7003083 7003083 7003083 * Strainer- Fuel Inlet 14 7006129 7006129 7006129 7009463 7009463 Air Horn Ass If. 15 7000204 7000204 7000204 7000204 7000204 Piston-Power 16 70001 99 7000199 70001 99 7000199 7000199 Floot Assv. 17 7001595

. 7001595 7001595 7001595 7001595 Pin-Float Hince

18 7006134 7006134 7006134 7006134 7006134 *Needle and Seat Assv. 19 7001613 7001613 7001613 7001613 7001613 *Needle and Seat Gasket 20 7006079 7006079 7006079 7006079 7006079 * Stroi ner- Needle Seat

BULLETIN 9C-504 PAGE 2 OF 5

1954 HY DRAMATIC

7005900 111 us. No.

?1 , ... ·.4597

' ' 7001604 ?1 7001605 ?A / 1"•'1'0

' "' ,.· .. ,711 7 ?I.. 7006059 27 7003838 ?II 7005286 ?0 / 111 ,,', l 10 "l l"I /I llJ,'' -,1::;5

11 7006299 12 451910 "l 'l 7007803 14 7002649 34 7002649 , "' 7001 608 36 700161 3 37

'lA 7007502 39 7000248 40 7004821 41 7004285 4? 7002760 41 7006136 44 1875051 45 7000196 46 7006837 47 7000191 48 7007627 49 7005972 50 7004748 51 52 7000614 53 131958 54 7000189 55 7003135 56 700281 4 57 7001637

58 7006887 59 7004324 60 7005188 61 121744 62 7004395 63 7003561 64 7006835 65 7005032 66 7003137 67 7000246 68 7005032 69 7001619 70 7003176 71 72 7003122 73 7003176 74 7000241 75 7005032 76 7006132 77 70::>4402 78 7003190 79 7006479 80 7006478 81 56!!292

A2 83 84 85 86 lS/

1954-55 SYNCROMESH

7006000

7004597 7001604 7001605 700212u 7002117 7006059 7003838 7005286 7006130 7006055 7006459

451910 7007803 7002649 7002639 7001608 7001613

.

7007502 7000248 7004821 7004285 7002760 7006136 1875051 7000196 7006837 7000191 7007627 7008247 7004748

7000614 131958

7000189 7003135 7002814 7001637

7006887 7004324 7005188

121744 7004395 7003561 7006835 7005032 7003137 7000246 7005032 7001619 7003176

7003122 7003176 7000241 7005032 7006132 7004402 7003190 7006479 7006478 568292

1955 1956 HYDRAMATIC SYNCROMESH HYDRAMATIC

7007000 7007222 7007221

FLOAT BOWL PARTS

7C04597 7004597 7004597 7001604 7001604 7001604 7001 60.5 7001605 7001605 /UU212U /• 11 12l2U /UU21Z{J 7002117 7002117 7002117 7006059 7006059 7006059 7003838 7003838 7003838 7005286 7005286 7005286 7006130 7009466 7009466 7006055 7009497 7009497 7006299 7008955 7008955

451910 451910 451910 7007803 7007803 7007803 7002649 7001860 7001860 7002649 7008667 7008667 7001608 7009349 7009349 700161 3 7001 613 7001613

7008958 7008958

CHOKE HOUSING PARTS

7007502 7007502 7007502 7000248 7008950 7008950 7004821 7004821 7004821 7004285 7004285 7004285 7002760 7002760 7002760 7006136 7009792 7009792 1875051 1875051 1875051 7000196 7000196 7000196 7006837 7008547 7008547 7000191 7000191 7000191 7007627 7007627 7007627 7008247 7008247 7008247 7004748 7004748 7004748

7006846 7006846 7000614 7000614 7000614

131958 131958 131958 7000189 7000189 7000189 7003135 7003135 7003135 70028 14 7002814 7002814 7001637 7001637 7001637

THROTTLE BODY PARTS

7006887 7009256 7009256 7004324 7004324 7004324 7005188 7005188 7005188

121744 121744 121744 7004395 7004395 7004395 7003561 7003561 7003561 7006835 7006835 7006835 7005032 7005032 7005032 7003137 7003137 7003137 7000246 7000246 7000246 7on5032 7005032 7005032 7006959 7006959 7006959 70:)3176 7003176 7003176 1901800 1901800 1901800 7003122 7003122 7003122 7003176 7003176 7003176 7000241 7000241 7000241 7005032 7005032 7005032 7007135 7009467 7009467 7004402 7004402 7004402 7003 190 7003190 7003190 7006479 70::>6478

568292 568292 568292

THROTTLE RETURN CHECK PARTS

I ·J~071-

- 7008980 7008987

148072 7008480

120380

YEAR APPLICATION

CARBURETOR No. -

* Sp rina-Pump Return * Screen-Pump Inlet

. ~ Retoiner-Pump Screen T Boll-Pumo Inlet !Aluminum! *Boll-Pu me Discharae (Steel) *Sor ina- Pumo Discharae Ball *Guide-Pume Discharae Serina

Siaht Plua Float Bowl Assv, Venturi Cluster-Primarv Venturi Cluster-Seconda rv Screw-Cluster Attachina

*Gasket-Venturi Cluster Jet-Primary-Standard Jet-Secondarv Standard

*Power Valve Assembly *Gasket-Power Valve

Aux ilia ry Throttle Valve Assembly

* Gasket-Choke Housin Choke Housina Assembly I Screw-Choke Hsa. I

Baffle Plate *Gasket-Stat Cover

Stat Cover Coil and Gasket Assemblv Tri o lever Screw Trio lever Choke lever and Collar Valve-Choke Screw-Choke Valve Piston- Choke Pin-Choke Piston Retainer- Stat Cover-Toothed Retainer-Stat Cover-Plain Screw-Stat Cover Attachina Choke Shaft and lever Assemblv Plua-Exoansion Plua-lead Ball {Smalll Plug- lead Ball (large)

*Gasket- Throttle Bodv Screw-Throttle Body-Lor e Screw-Throttle Body-Small lockwosher-Smoll Screw Cam-Fast Idle Screw-Fast Idle Com Attachina Choke Rod

* Clio-Choke Rod *Clio-Pumo Rod-Uooer

Pume Rod *Clin-Pumn Rod- lower

Screw-Idle Stoo Serina-Idle Stoe Screw Wosher-Serina Retaininn Screw-Fast Idle Adiustina Serina- Fast Idle Adiustina Screw link-Sec. lever

*Clio-Sec. lever link Th rottle Body Assy.

*Needle-Idle Adiustina Serina-Idle Adiust ina Needle Sec. Throttle Ret. Sorin and Screws Kit Shaft Overri d? Serina and Screws Kit

*Gasket-Flo nae

T . ' N"•• ... ... ll\

Throttle Return Check Assv. Check Valve Assv. Connector-Tube Screw-Return Check Mountina {1 l lockwasher- Mounting Screw (1)

'__. ...

Rochester Carburetors BULLETIN 9C-504 PAGE 3 of 5 MODEL 4GC DATE 2-15-57 1954-56 OLDSMOBILE SUPER 88 and 98

---~~--~_::::::::..__..!:.A~D~J~US~T~M~E~N~TS~AND_S_P_EC_IF_IC_A_T_IO_N_S __ ~--------------. 1 GAUGE SHOULD JUST

TOUCH FLOAT AT HIGHEST POINT

BEND FLOAT ARM TO ADJUST

FLOAT MUST BE CENTERED

BETWEEN GAUGE LEGS

FLOAT LEVEL ADJUSTMENT

SETTING l~". USE GAUGE BT-89

With air air horn gasket in place, position gauge over floats and against curvature in air horn bore. Bend float arms at rear of assembly so Boats just touch gauge. then bend float arms horizontally to center each pontoon between gauge legs. Repeat on opposite Boats.

2 BEND FLOAT TANG TO ADJUST FOR PROPER SETTING

'-... ME'.ASURE 2 114 • FROM

GASKET SURFACE TO

BOTTOM OF FLOAT

FLOAT DROP ADJUSTMENT

SE'l"l'ING 2-1/4", USE GAUGE BT-93 OR SCALE

Bend the float tang as required to obtain a distance of 2J;.i" from the gasket surface to the bottom of the Boat, with the floa~ hanging free.

3 BEND ROD

TO ADJUSi FOR

PROPER PUMP ROD SETTING

MEASURE FROM TOP OF

AIRHORN TO BOTTOM OF PUMP

PLUNGER SHAFT

THROTTLE VALVES COMPLETELY CLOSED

PUMP ROD SETTING

SETTING 1-1 /16", USE TOOL BT-18

With the fast idle and idle stop screws backed off and the throttle valves completely closed, bend the pump rod as shown to obtain a measurement of 1-1 /16" from the top of the air horn casting to the bottom of the pump plunger shaft.

4

VENT VALVE JUST CLOSED

BEND TANG TO ADJUST --.. ..... FOR PROPER SETTING

SPECIFIED GAUGE BETWEEN THROTTLE VALVE AND BORE ON PRIMARY SIDE ,OPPOSITE

IDLE ADJUSTING NEEDLES

IDLE VENT ADJUSTMENT

With the primary throttle valves closed against a .063 wir<' gauge (BT-79), bend the idle vent tang with Bending Tool BT-69 so that the tang just touches the face of the valve.

5

AUTOMATIC CHOKE ADJUSTMENT

7005900, 7007000..-SETTING INDEX 7006000, 7007221. 7007222..-SETTING~ I NOTCH LEAN

Loosen the three retaining screws and rotate the stat cover counterclockwise against the coil tension until the index ma rk is in the proper position with the index point on the housing.

6

FAST IDLE SCREW ON HIGHEST STEP OF FAST IDLE CAM

FAST IDLE ADJUSTMENT

SE'l"l'ING .024, USE GAUGE BT-90 1500 R.P.M.

Turn the fast idle screw against the highest step of the fast idle cam, to obtain a clearance of .024 between the throttle valve and bore, opposite the idle adjusting needles.

BULLETIN 9C-504 PAGE 4 OF 5

7

BEND ROD ro ADJUST FOR PROPER

CHOKE ROD SETTING

SPECIFIED GAUGE BETWEEN UPPER EDGE OF CHOKE VALVE AND DIVIDING WALL OF AIRHORN

FAST IDLE SCREW ON SECOND STEP

AGAINST HIGH STEP

CHO KE ROD ADJUSTMENT

SETTING .052, USE GAUGE BT-68. TOOL BT- 18

With the fast idle screw resting on the 2nd step and against the high step of the fast idle cam, bend the choke rod as shown to obtain a clearance of .052" between the choke va lve edge and the dividing air horn wall .

8

0

SPECIFIED GAUGE BETWEEN UPPER EDGE OF CHOKE VALVE AND DIVIDING WALL OF AIRHORN

THROTTLE VALVES WIDE OPEN

BEND TANG TO ADJUST FOR PROPER SETTING

...I

UN LOADER ADJUSTMENT

SE'I*I'ING . 115, USE TOOL BT-69. GAUGE BT-90

Bend the unloader tang on the fast idle cam to obtain a clear­ance of . I I 5 between the choke valve edge and the dividing air horn wall with the throttle valves wide open.

9 CHOKE VALVE FULLY CLOS E

•

•

INSERT FEELER GAUGE BETWEEN LOCKOUT LEVER AND FAST IDLE CAM

BEND TANG TO ADJUST FOR PROPER

SETTING

If lt(f ftf ff ifif fl]1l//t I~,

I

• I

SECONDARY LOCKOUT ADJUSTMENT

SE'l*l'ING .015. USE TOOL BT-91 ·A With the choke valve fully closed, bend the lockout lever as shown to obtain .015 clearance· between the cam and the widest surface of the lockout lever at the point shown.

10

CHOKE VALVE WIDE OPEN INSERT FEELER GAUGE

BETWEEN LOCKOUT LEVER AND FAST IDLE. CAM

• I

' •

SECONDARY CONTOUR ADJUSTMENT

SETTING .030, USE TOOL BT-69

With the choke valve wide open, bend the lockout lever as shown to obtain .030 clearance between the cam and the narrowest surface of the lockout lever at the point shown.

, l WHEN TURNING ADJUSTING SCREW, HOLD PLUNGER WITH WRENCH TO PREVENT DAMAGE TO DIAPHRAGM

WITH ENGINE OFF ANO SCREW STI LL ON HIGH STEP. ADJUST THE SET SCREW TO .02 8 "

CLEARANCE BETWEEN THE

•

SCREW HEAD a THROTTLE LEVER

• SCREW ON HIGH STEP OF CAM

THROTTLE RETURN CHECK ADJUST ME NT

Place the fast idle screw on the high step o f the fast idle cam. W ith the engine in neutral adjust the fast idle speed to 1500 RPM. Shut engine off and with the fast idle screw on the high step of the fast idle cam adjust the plunger screw on the throttle return check to obtain a .028" clearance between the screw head and the throttle lever.

CAUTION: Always hold the plunger with a wrench while adjusting the screw to avoid damage to the dia phragm.

Carburetor No.

SMALL VENTURI

LARGE VENTURI

MAIN METERING JETS

IDLE NEEDLE HOLES

IDLE HOLES - FIRST

IDLE HOLES - SECOND

SPARK DRILLINGS

PUMP DISCHARGE HOLES

POWER RESTRICTIONS

CHOKE RESTRICTION

IDLE TUBE RESTRICTION

LOWER IDLE BLEED

ADJUSTMENTS

FLOAT LEVEL

FLOAT DROP

PUMP ROD

IDLE VENT

AUTO CHOKE

FAST IDLE

CHOKE RO D

UNLOADER

SECONDARY LOCKOUT

SECONDARY CONTOUR

THROTTLE RETURN CHECK

Rochester Carburetors MODEL 4GC

1954 - 56 OLDSMOBILE ''SUPER 88'' - ''98''

ADJUSTMENTS AND SPECIFICATIONS

QUICK-REFERENCE SPECIFICATIONS

7005900 H.T. 7007221 H.T. 7007000 H.T. 7006000 Syn. 7007222 Syn.

PRIM. SEC. PRIM. SEC. PRIM. SEC.

1/.i ,, v. ,, · 4 1/.i ,, 1/.i ,, v.. II 1/.i "

1-1 I 64" 57/ 64" 1-1/ 64" 57/ 64" 11/a II 1 lf.i "

.049 .049 .049 .039 .055 .067

.040 - .040 - .046 -

.031 - .031 - .030 -

.026 - .026 - .026 -

.070 - .070 - .070 -

.026 - .026 - .026 -

.030 - .030 - .048 -

.086 - .086 - .093 -

.030 - .030 - .033 -

.040 .040 .040 • - - -DIMENSIONS DIMENSIONS DIMENSIONS

1 o/a" 1 o/a II 1 s;8 "

21/.i,, 21/.i " 21/.i "

1-1 / 16" 1-1 / 16" 1-1/ 16"

.063 .063 .063

INDEX 1 NOTCH LEAN 1 NOTCH LEAN

.024 .024 .024

.052 .052 .052

.115 . 11 5 .115

.015 .015 .015

.030 .030 .030

- - .028

TUNE-UP SPECIFICATIONS 1954-56 SPARK PLUG GAP .030

BREAKER POINT GAP .016

CAM DWELL 26° - 33 °

IG NITION TIMING 5 ° B.T.C. AT 850 R.P.M. WITH DIST. VACUUM LINE DISC6NNECTED

TAPPET CLEARANCE HYDRAULIC

IDLE - R.P.M. HYDRAMATIC 400 R.P.M. IN " DRIVE" SYNCHROMESH 425 R.P.M. IN " NEUTRAL"

FAST IDLE - R.P.M. 1500 R.P.M.

BULLETIN 9C-504

PAGE 5 OF 5

DATE: 2-15-57

TOOL No.

BT-89

BT-93 OR SCALE

SCALE

BT-79

BT-90

BT-68

BT-90

FEELER GAUGE

FEELER GAUGE

FEELER GAUGE

CARBURETOR TOOLS AND GAUGES AS LISTED ARE AVAILABLE THROUGH UMS DISTRIBUTORS

A GENERAL MOTORS PRODUCT A UNITED MOTORS -AC LINE

UNITED MOTORS SER VICE-AC DIVI SION , GENERAL MOTORS PRODUCTS _OF CANADA LIM I TE D, OSHAWA, ONTARIO