Carburetor - Rochester e4me 4-bbl GMC Vandura I

COMPONENT TESTING

Note. Specific component testing information not available. Refer to any tests performed during REMOVAL & INSTALLATION or OVERHAUL procedures

APPLICATION

GENERAL MOTORS (ROCHESTER) CARBURETOR NO.

IDENTIFICATION

The Rochester E4ME carburetor number is stamped vertically on the float bowl, near secondary throttle. If float bowl is replaced, follow manufacturer's instructions contained in service package to transfer part number to new float bowl. Some models have machined pump wells to reduce the pump well taper.

The E4ME Quadrajet carburetor is used nationwide with the Computer Command Control (CCC) system. The first letter "E" indicates the carburetor is a part of the CCC system. The final letter, if "E", indicates the carburetor is equipped with an electric choke.

Carburetor Identification Label Orig part no. must be trans from old float bowl if new one is inst. Scheme 1

DESCRIPTION

The E4ME carburetor is a 2-stage, downdraft design. Each bore has a triple venturi system. The secondary side is composed of 2 large throttle bores, using the air valve principle, in which fuel is metered in direct proportion to the amount of air passing through the secondary throttle bores. A baffle is attached to the secondary side of the air horn, above the main well bleed tubes. This deflects incoming air to improve secondary nozzle operation on heavy acceleration.

The E4ME uses an electrically-actuated choke assembly. All E4ME models have 2 vacuum break diaphragm assemblies, the front and rear.

The E4ME model is used in conjunction with the Computer Command Control (CCC) System. The carburetor is equipped with an electrically-actuated mixture control solenoid mounted in the float bowl. Fuel metering is controlled by stepped metering rods that operate in removable jets.

All models include tamper-resistant factory settings of the mixture control solenoid rich mixture stop screw and lean mixture screw, idle air bleed valve, TPS, ISC, ISS and idle mixture screws. No attempt should be made to adjust these except during major overhaul or replacement of air horn, float bowl or throttle body. Both electric and hot air chokes have riveted covers which must not be removed except for major overhaul.

The carburetor may be equipped with an Idle Speed Control (ISC) on the fuel bowl. Controlled by the ECM, the ISC controls the normal curb idle speed and acts as a dashpot on deceleration and throttle closing. On vehicles without an ISC, but with air conditioning, an Idle Speed Solenoid (ISS) maintains a specific idle speed during A/C operation.

ELECTRIC CHOKE

Note. This test should be performed when air temperature is 60-80°F (15-27°C).

1. Allow choke to cool to permit full closing of choke blade when throttle is opened slightly. Start engine and time the interval required for choke blade to reach full open position. (Start timing when engine starts). If choke blade does not fully open within 3 1/2 minutes, proceed with test.
2. With engine running, check voltage at choke heater connection. If voltage is about 12-15 volts, replace electric choke unit. If voltage is low or zero, check all wires and connections and repair as required. Power for choke unit is through the oil pressure switch. Ensure switch circuitry is good.
3. If procedure in step 2 does not correct the problem, replace oil pressure switch.

ADJUSTMENTS

Note. For all on-vehicle adjustments not covered in this article, see appropriate TUNE-UP article.

ANGLE GAUGE ADJUSTMENT TOOL

Manufacturer recommends that some carburetor adjustments be performed using a choke valve angle gauge (Kent-Moore tool No. J-26701). While preparations and actual adjustment may vary with each individual adjustment, the procedure for using the angle gauge to check the choke valve angle remains the same. Use the following procedure to perform adjustments requiring the use of the choke valve angle gauge.

Choke Valve Angle Gauge This gauge must be used to perform some adjustments. Scheme 2

1. Rotate degree scale on angle gauge so that 0° mark is opposite pointer.
2. With choke valve closed, place angle gauge magnet squarely on choke valve.
3. Rotate leveling bubble on angle gauge until it is centered.
4. Rotate degree scale until specified degree mark is opposite pointer.
5. Now perform individual adjustment preparation as outlined in the following carburetor adjustments requiring an angle gauge.
6. If bubble is centered, adjustment is correct. If not, adjust carburetor as outlined in adjustment procedure.

FLOAT LEVEL (WET SETTING)

Note. This is an on-vehicle adjustment.

Scheme 3

1. With engine running at idle and choke wide open, carefully insert float gauge into vent slot or vent hole (next to air cleaner mounting stud) in air horn. Allow gauge to float freely. (Scheme 3) NOTE: Pressing down on float gauge could result in float damage or carburetor flooding. (Scheme 3): Wet Float Level Adjustment Allow float gauge to float freely.
2. With gauge floating freely, observe mark on gauge which aligns with top of casting (at eye level). Reading should be within 1/16" of specified float level. Incorrect fuel pressure will affect fuel level.
3. If reading is not within 1/16" of specified float level, remove carburetor. Remove air horn and perform Float Level (Dry Setting) adjustment.

Start Here

1. Remove air horn and gasket from float bowl. Hold float retainer down firmly. Lightly push float down against the needle. (Scheme 4)
2. Position a "T" scale over toe of float at a point 3/16" from end of float toe. Measure distance from top of float bowl casting to top of float.
3. If float level setting varies more than 1/16" from specified setting, proceed as follows

Dry Float Level Adjustment Follow procedures to properly adjust float level. Scheme 4

Float Level Too High

1. a) Hold float retainer clip firmly in place.
2. b) Push down on center of float pontoon until correct float level setting is obtained.

Float Level Too Low

1. a) Lift out metering rods. Remove solenoid connector screws.
2. b) Turn lean mixture solenoid screw clockwise, counting and recording number of turns required to lightly seat screw in float bowl.
3. c) Turn screw counterclockwise and remove. Lift solenoid and connector from float bowl.
4. d) Remove float and bend arm up to adjust. Make sure float is correctly aligned after adjustment.
5. e) Reinstall components in reverse order that they were removed. Back out solenoid mixture screw number of turns noted in step b.

SOLENOID LEAN MIXTURE SCREW (BENCH ADJUSTMENT)

Note. This is a preliminary adjustment only. It is required to ensure that lean mixture screw is set close to specifications prior to final adjustment. Final adjustment must be made with carburetor installed and engine running. See appropriate TUNE-UP article.

1. Install plastic aneroid cavity insert beneath mixture control solenoid connector in float bowl, if used. Ensure insert is installed with inset aligned with recess of bowl cavity and seated flush with bowl casting surface. Tang on upper lip of insert goes in deep slot in bowl closest to fuel inlet nut.
2. Install mixture control solenoid screw tension spring between raised bosses next to float hanger pin. Carefully install mixture control solenoid in float chamber. Align pin on end of solenoid with hole in raised boss at bottom of bowl. Align connector wires to fit in slot in bowl or plastic insert, if used.
3. Install solenoid lean mixture screw through hole in solenoid bracket and tension spring in float bowl. The first 6 threads of the mixture screw should be engaged to assure proper installation.
4. Install mixture control solenoid gauging tool over throttle side metering jet rod guide. Temporarily install solenoid plunger. (Scheme 5)
5. Hold solenoid plunger against solenoid stop. Using a "double D" wrench, slowly turn lean mixture screw clockwise until solenoid plunger just contacts gauging tool. (Scheme 5)
6. Adjustment is correct when solenoid plunger is contacting BOTH the solenoid stop and gauging tool. Remove solenoid plunger and gauging tool.

Solenoid Lean Mixture Screw Bench Adjustment Lean mixture screw should be installed with first 6 threads engaged in float bowl. Scheme 5

SOLENOID RICH MIXTURE STOP SCREW (BENCH ADJUSTMENT)

Note. This is a preliminary adjustment only. It is required to ensure that rich mixture stop screw is set close to specifications prior to final adjustment. Final adjustment must be made with carburetor installed and engine running. See appropriate TUNE-UP article.

1. With solenoid lean mixture screw properly set and air horn installed, insert plastic float gauge in vertical "D" shaped vent hole in air horn casting.
2. With float gauge installed, read mark (in inches) on gauge that lines up with top of air horn casting at eye level. Record reading. Lightly depress float gauge and again read mark on gauge that lines up with top of casting. Record reading.
3. Subtract the 2 readings taken in step 2. This difference is the total solenoid travel. Using a "double D" wrench, turn rich mixture stop screw until total solenoid travel (difference between readings) is 4/32". (Scheme 6)
4. After adjustment, install lean mixture screw plug and rich mixture stop screw plug. Plugs must be installed to seal settings and to prevent fuel vapor loss. (Scheme 7)

Solenoid Rich Mixture Stop Screw Bench Adjustment Air horn must be properly installed prior to adjustment. Scheme 6

Inst. Lean Mixture Screw Plug & Rich Mixture Stop Screw Plug Plugs seal settings and prevent loss of fuel vapor. Scheme 7

IDLE MIXTURE (BENCH ADJUSTMENT)

Note. This is a preliminary adjustment only. It is required to ensure that mixture screws and idle air bleed valve are set close to specifications prior to final adjustment. Final adjustment must be made with carburetor installed and engine running. See appropriate TUNE-UP article.

1. With air horn properly installed, lightly seat mixture screws. Back out 3 turns.
2. The idle air bleed valve is sealed with a riveted cover. This cover should not be removed unless required for cleaning, part replacement, improper dwell readings, or if Computer Command Control System Performance Check indicates that carburetor requires adjustment.
3. If idle air bleed cover was previously removed, or if conditions described in step 2 are met, check idle air bleed valve for a letter inscribed on top of valve. This will determine the correct on-vehicle adjustment procedure.
4. To adjust idle air bleed valve, if required, insert air bleed valve gauging tool in throttle side "D" shaped vent hole in air horn casting. Upper end of tool should be positioned over open cavity next to valve. (Scheme 8)
5. Hold the gauging tool down lightly so solenoid plunger is against solenoid stop. Adjust air bleed valve so gauging tool will pivot over and just contact top of valve. (Scheme 8)

Idle Mixture Bench Adjustment Final adjustments must be performed w/ carb installed and eng running. Scheme 8

ACCELERATOR PUMP ROD

No pump adjustment is required on carburetors for the Computer Command Control system.

AIR VALVE SPRING

1. Use hex wrench to loosen lock screw. Turn tension adjusting screw counterclockwise until air valve opens part way.
2. Turn tension adjusting screw clockwise until air valve just closes. Then turn adjusting screw clockwise specified number of turns. (Scheme 9)
3. Hold adjusting screw and tighten lock screw. Apply lithium base grease to lubricate contact area.

Air Valve Spring Adjustment Apply lithium base grease to lubricate contact area. Scheme 9

CHOKE COIL LEVER

Note. Choke coil cover uses rivets in place of retaining screws. If necessary to remove choke coil cover, refer to Disassembly and Reassembly procedures in this Section.

1. Remove retaining rivets. Remove choke cover and coil assembly from choke housing. (Scheme 10)
2. Position fast idle speed cam follower on high step of fast idle cam.
3. Push up (counterclockwise) on choke coil tang to close choke valve.
4. Insert specified drill or pin gauge in hole provided in choke housing. Lower edge of choke lever inside housing should just touch drill or pin gauge.
5. To adjust, bend choke rod. (Scheme 10)

Note. Electric choke units do not use a gasket between choke cover and choke housing.

Choke Coil Lever Adjustment Bend choke rod to adjust. Scheme 10

CHOKE ROD (FAST IDLE CAM)

Note. Choke coil lever adjustment must be correct before performing this adjustment. Fast idle speed adjustment must be performed using the Emission Control Tune-Up Decal with carburetor installed and vehicle running. Adjustment is performed with choke valve angle gauge. See procedure at beginning of Adjustments. DO NOT remove rivets and choke cover to perform this adjustment.

1. Attach rubber band to Green tang of intermediate choke shaft. Open throttle to allow choke valve to close. Set up angle gauge.
2. Place fast idle speed cam follower on second step of fast idle cam against shoulder of highest step. If cam follower does not contact cam, turn in fast idle speed screw additional turns. (Scheme 11)
3. Bubble on choke angle gauge should be centered with specified angle mark opposite pointer.
4. To adjust, bend tang on fast idle cam until bubble of choke valve angle gauge is centered.

Choke Rod (Fast Idle Cam) Adjustment Bend tang on fast idle cam to adjust. Scheme 11

PRIMARY (FRONT) VACUUM BREAK

Note. Choke coil lever and choke rod (fast idle cam) adjustments must be correct before performing this adjustment. Adjustment is performed with choke valve angle gauge. See procedure at beginning of Adjustments. DO NOT remove rivets and choke cover to perform this adjustment.

1. Attach rubber band to Green tang of intermediate choke shaft. Open throttle to allow choke valve to close. Set up angle gauge.
2. Using an outside vacuum source of at least 18 in. Hg, seat primary (front) vacuum break diaphragm. If air valve rod restricts vacuum break plunger from being seated, bend rod to allow full plunger travel. Be sure leaf bucking spring is seated against lever, if equipped. (Scheme 12) NOTE: On models equipped with air bleed, remove rubber cover from filter and plug vacuum tube with a piece of tape. If bleed hole is in end of diaphragm, plug hole in end of diaphragm with a piece of tape. Remove tape after completing adjustment.
3. Bubble on choke valve angle gauge should be centered with specified degree mark opposite pointer.
4. To adjust, turn vacuum break adjustment screw with vacuum still applied. Adjustment is correct when bubble of choke valve angle gauge is centered.

Primary (Front) Vacuum Break Adjustment Turn vacuum break adjustment screw to adjust. Scheme 12

SECONDARY (REAR) VACUUM BREAK

Note. Choke coil lever and choke rod (fast idle cam) adjustments must be correct before performing this adjustment. Adjustment is performed with choke valve angle gauge. See procedure at beginning of Adjustments. DO NOT remove rivets and choke cover to perform this adjustment.

1. Attach rubber band to Green tang of intermediate choke shaft. Open throttle to allow choke valve to close. Set up angle gauge.
2. Using an outside vacuum source of at least 18 in. Hg, seat secondary (rear) vacuum break diaphragm. If air valve rod restricts vacuum break plunger from being seated, bend rod to allow full plunger travel. Be sure leaf bucking spring is compressed, if equipped. (Scheme 13) NOTE: On models equipped with air bleed, remove rubber cover from filter and plug vacuum tube with a piece of tape. If bleed hole is in end of diaphragm, plug hole in end of diaphragm with tape. On delay models with air bleed, plug end cover with an accelerator pump plunger cup. Remove tape or cup after completion of adjustment.
3. Close choke by pushing up on choke coil lever or vacuum break lever tang. Hold choke closed with a rubber band.
4. Bubble on choke valve angle gauge should be centered with specified degree mark opposite pointer.
5. To adjust on models equipped with hex adjustment, use a 1/8" hex wrench to turn adjustment screw in rear cover of vacuum break with vacuum still applied.
6. To adjust on models without hex adjustment, support rod at "S" and bend vacuum break rod with vacuum still applied. Adjustment is correct when bubble of choke valve angle gauge is centered.

Secondary (Rear) Vacuum Break Adjustment Turn screw or bend vacuum break rod to adjust. Scheme 13

AIR VALVE ROD - FRONT

1. Using an outside vacuum source, at least 18 in. Hg, seat primary (front) vacuum break diaphragm. Plug purge bleed hole (if equipped) with masking tape. Hole is located in end of diaphragm. (Scheme 14)
2. Make sure air valve is completely closed. Measure clearance between rod and end of slot in lever. Clearance can be checked using a specified drill or pin gauge. (Scheme 14)
3. Bend rod at point shown to adjust clearance in slot to.025" with vacuum still applied. Remove tape and reconnect vacuum hose to diaphragm.

Air Valve Rod Adjustment - Front Air valve must be completely closed. Scheme 14

AIR VALVE ROD - REAR

1. Using an outside vacuum source, at least 18 in. Hg, seat secondary (rear) vacuum break diaphragm. Plug purge bleed hole (if equipped) with masking tape. Hole is located in end of diaphragm.
2. Make sure air valve is completely closed. Measure clearance between rod and end of slot in lever. Clearance can be checked using a specified drill or pin gauge. (Scheme 15)
3. Bend rod at point shown to adjust clearance in slot to.025" with vacuum still applied. Remove tape and reconnect vacuum hose to diaphragm.

Air Valve Rod Adjustment - Rear Air valve must be completely closed. Scheme 15

AUTOMATIC CHOKE

Note. Choke coil cover is retained in place with rivets. No adjustment is required. If necessary to remove choke coil cover, refer to Disassembly and Reassembly procedures in this Section. Only remove choke cover if major overhaul is required or if choke cover requires replacement.

CHOKE UNLOADER

Note. Choke coil lever and choke rod (fast idle cam) adjustments must be correct before performing this adjustment. Adjustment is performed with choke valve angle gauge. See procedure at beginning of Adjustments. DO NOT remove rivets and choke cover to perform this adjustment.

1. Attach rubber band to Green tang of intermediate choke shaft. Open throttle to allow choke valve to close. Set up angle gauge. Hold secondary lockout lever away from pin. (Scheme 16)
2. Hold throttle lever in wide open position. Bubble on choke valve angle gauge should be centered with specified degree mark opposite pointer.
3. To adjust, bend choke unloader tang on fast idle lever until bubble of choke valve angle gauge is centered. Remove gauge.

Choke Unloader Adjustment Bend tang to adjust. Scheme 16

Lockout Lever Side Clearance

1. Hold choke valve and throttle valves completely closed. (Scheme 17)
2. Measure secondary throttle valve lockout specified side clearance between pin and lockout lever.
3. Specified lockout lever side clearance is.015". To adjust, bend pin.

Secondary Throttle Valve Lockout Adjustment. Scheme 17

Lockout Lever Opening Clearance

1. Push down on tail of fast idle cam and open choke valve completely.
2. Measure secondary throttle valve lockout specified opening clearance between end of pin and toe of lockout lever.
3. Specified clearance is .015", To adjust, file end of lock out pin. Make sure all burrs are removed.

DISASSEMBLY

Note. Before performing any service on carburetor, it is essential that carburetor be placed on a Holding Fixture (J-9789-118) to prevent damaged to throttle valves.

Air Horn

1. Remove ISC or ISS attaching screws, bracket and assembly. Remove upper choke lever from end of choke shaft by removing retaining screw. Rotate upper choke lever to remove choke rod from slot in lever. Remove choke rod from lower lever inside float bowl casting. Remove rod by holding lower lever outward with small screwdriver and twisting rod counterclockwise.
2. Remove secondary metering rods by removing small screw in top of metering rod hanger. Lift up on metering rod hanger until secondary metering rods clear air horn. Metering rods may be disassembled from hanger by rotating ends out of holes in end of hanger.
3. Using a small drift punch, drive pump lever pivot pin (roll pin) inward until pin is against air cleaner locating boss on air horn casting. Disconnect pump rod from pump lever. Remove vacuum hose from front vacuum break unit and note location for reassembly reference. Remove 11 air horn-to-float bowl screws. Remove 2 countersunk screws located near venturi. CAUTION: Be careful when removing roll pin to avoid damage to pump lever bosses.
4. Remove secondary air baffle deflector (if equipped) from beneath 2 center air horn screws. Remove air horn from float bowl by lifting straight up. Air horn gasket should remain on float bowl. NOTE: Use care not to damage mixture control solenoid connector, TPS adjustment lever, and small tubes protruding from air horn. DO NOT attempt to remove small tubes.
5. Remove primary (front) vacuum break diaphragm. Remove air valve rod from vacuum break and air valve lever. Using fingers only, remove TPS plunger by pushing plunger up through air horn seal. If air horn is removed, lean mixture screw plug and rich mixture stop screw plug must be removed from air horn. Drive plugs out from bottom side. Discard plugs.
6. Remove TPS seal by inverting air horn and remove staking from around seal retainer with a small screwdriver. Remove and discard retainer and seal. Use care removing retainer and seal to prevent damage to air horn casting.
7. Further disassembly of air horn assembly is not required for cleaning purposes. Choke valve and choke valve screws, air valve and air valve shaft should not be removed. Instructions for replacing the air valve closing spring and plastic cam are included in service kit.
8. The air horn has an idle air bleed valve which is preset and sealed at the factory. The idle air bleed valve should not be removed unless "System Performance Check" of Computer Command Control system indicates need for adjustment or repair. NOTE: Air horn assembly, with idle air bleed valve installed, should be cleaned only in low volatile cleaning solvent. Do not place air horn (with idle air bleed valve) in carburetor cleaner. No tamper-resistant plug should be removed during normal carburetor or mixture control solenoid has been diagnosed as cause of poor engine performance.
9. If necessary to replace idle air bleed valve or disassemble air horn for immersion in carburetor cleaner, cover internal bowl vents and air inlets to bleed valve with tape. Drill off rivet heads of bleed valve cover with a .110" (No. 35) drill. Drive remainder of rivet out of tower with drift and small hammer. Lift out cover over valve and remove remaining rivet pieces from inside tower.
10. After removing cover, check for letter identification on top of idle air bleed valve. This will determine the necessary adjustment procedure after reassembly. Turn valve counterclockwise and remove from air horn. Remove and discard "O" ring seals from air bleed valve. Air bleed valve is serviced as a complete assembly only.

Note. A missing air valve cover indicates that idle air bleed valve setting has been changed from original factory setting.

Float Bowl

1. Remove solenoid metering rod plunger by lifting straight upward. Remove air horn gasket by lifting off of dowel locating pins. Discard gasket.
2. Remove pump plunger and return spring from pump well. Remove staking holding TPS in bowl. To do so, protect gasket surface by laying a flat piece of metal across casting.
3. Using a small screwdriver, lightly depress and hold TPS down against spring tension. Carefully remove staking from around TPS by prying upward with a small chisel against the metal piece (not bowl casting).
4. Push up from bottom on electrical connector and remove TPS and connector assembly from bowl. Use care not to damage sensor during removal. Remove spring from bottom of TPS well. Remove plastic filler block from float valve.
5. Carefully remove each metering rod from metering jet. Make sure return spring is removed with each rod. Remove return spring by sliding it off metering rod.
6. Remove screws connecting mixture control solenoid connector to float bowl. DO NOT remove connector from float bowl at this time. Using adjusting tool (J-28696), remove lean mixture screw. Carefully lift solenoid and connector assembly from bowl. NOTE: DO NOT remove plunger return spring or connector from solenoid body. Solenoid and connector are serviced as an assembly.
7. Remove plastic insert from solenoid connector cavity in float bowl (if used). Remove solenoid screw tension spring (next to float hanger clip). Remove float assembly and needle valve by lifting straight up. Remove needle valve seat and gasket.
8. Remove large mixture control solenoid tension spring from boss on bottom of float bowl located between metering jets. Remove primary main metering jets (if necessary). NOTE: DO NOT attempt to remove secondary metering jets (metering orifice plates). Secondary jets are permanent and if damaged, float bowl must be replaced.
9. Remove accelerator pump discharge check ball retainer and check ball. Remove secondary air baffle, if replacement is required. Remove accelerator pump well baffle (if necessary).
10. If equipped, remove rear vacuum break hose and retaining screws. Rotate vacuum break to remove vacuum break link from slot in plunger head. DO NOT remove non-adjustable vacuum break link until after removal of choke assembly from float bowl.
11. Align a .159" (No. 21) drill on choke cover retaining rivets and drill only enough to remove rivet head. Using a drift and hammer, drive remainder of rivets out of choke housing. Remove 3 retainers and choke cover from choke housing. NOTE: DO NOT remove baffle plate from beneath thermostatic coil on choke cover of hot-air type chokes.
12. Remove retaining screw and washer from inside choke housing. Slide choke housing from float bowl. Remove rear vacuum break link from intermediate choke lever.
13. Remove secondary throttle valve lockout lever from float bowl. Remove lower choke lever from inside float bowl cavity by turning float bowl upside down. Remove coil lever retaining screw from end of intermediate choke shaft and remove lever.
14. Slide intermediate choke shaft from choke housing. Remove fast idle cam from intermediate choke shaft.
15. Remove intermediate choke shaft cup seal from float bowl insert. DO NOT remove insert. Remove fuel inlet nut, gasket and filter. Remove 3 throttle body-to-float bowl screws and throttle body.

Throttle Body

1. Remove accelerator pump rod from throttle lever by rotating rod until tang aligns with slot in lever. NOTE: Further disassembly of throttle body is not required for normal cleaning. Throttle valve screws are permanently staked in position. Throttle body is serviced as complete assembly. DO NOT remove mixture screw plugs unless diagnosis indicates the carburetor is cause of poor engine performance or idle mixture needles or throttle body must be replaced. If necessary to remove plugs, continue as follows
2. Turn throttle body over and position on a holding fixture with manifold side up. Make 2 parallel cuts in throttle body using small hacksaw, cutting on each side of idle mixture needle plug. Cuts should reach down to steel plug, but no more than 1/8" beyond locator points. Distance between saw marks will depend upon size of punch used.
3. Place a flat punch at a point near ends of saw marks. Hold punch at 45° angle and drive it into throttle body until casting breaks away, exposing steel plug.
4. Hold punch vertically and drive it into steel plug. Then hold punch at 45° angle and drive plug out of casting. Repeat process for remaining mixture needle. When removing or installing needles, refer to Idle Mixture (Bench Adjustment) procedure in this article.

Exploded View of Rochester E4ME Carburetor. Scheme 18

Note. Hardened steel plug will shatter. It is not necessary to remove plug completely. Remove just enough pieces to allow idle mixture adjusting tool to be used to remove mixture screws and springs. Idle mixture screw head has a "double-D" configuration and can also be removed using a piece of 7/32" copper tubing that has been partially flattened.

CLEANING & INSPECTION

1. Use a regular carburetor cleaning solution. Soak components long enough to thoroughly clean all surfaces and passages of foreign matter.
2. DO NOT soak any components containing rubber, leather or plastic. Particularly, do not soak air horn with idle air bleed valve installed, electric choke, ISS, ISC, TPS, thermostatic choke cover and coil, vacuum break diaphragms, pump plunger and other such parts.
3. Remove any residue after cleaning by rinsing components in a suitable solvent.
4. Blow out all passages with dry compressed air.

REASSEMBLY

Note. Use new gaskets and seals. Make sure that new gaskets fit correctly and that all holes and slots are punched through and correctly located.

Reassemble carburetor in reverse order of disassembly, noting the following

1. The intermediate choke shaft lever and fast idle cam are assembled correctly when tang on lever is beneath fast idle cam.
2. When installing float and retaining pin, make sure open end of float retaining pin faces accelerator pump well.
3. When installing fuel inlet valve, hook pull clip over edge of flat on float arm. DO NOT hook clip in holes in float arm.
4. When installing mixture control solenoid, make sure pin on end of solenoid aligns with hole in raised boss at bottom of float bowl.
5. Install, adjust and plug all screws to restore tamper-resistant design. NOTE: If choke coil cover was removed, it will be necessary to install service rivet retaining kit. Before installing cover, place fast idle screw on high step of fast idle cam. Align notch in cover with raised boss on housing cover flange and install rivets.
6. Place fast idle screw on high step of fast idle cam. Install choke coil cover if removed, aligning notch in cover with tab on cover retainer (supplied in service kit). Be sure coil tang engages pick-up lever. Install blind rivets. NOTE: On E4ME models, ground contact for electric choke is provided by metal plate located at rear of choke cover assembly. Do not install choke cover gasket between electric choke and housing.
7. Install air horn screws and tighten evenly, securely and in sequence shown in Fig. (Scheme 19).

Air Horn Screw Tightening Sequence Screws 1 and 2 are countersunk next to venturi. Scheme 19

SPECIFICATIONS

CARBURETOR ADJUSTMENT SPECIFICATIONS