Carburetor - Rochester e4me & e4med 4-bbl Chevrolet Pickup C10

COMPONENT TESTING

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

4.3L V6

GENERAL MOTORS (ROCHESTER) CARBURETOR NO. (4.3L V6)

5.7L V8

GENERAL MOTORS (ROCHESTER) CARBURETOR NO. (5.7L V8)

IDENTIFICATION

The Rochester E4ME or E4MED 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 and E4MED Quadrajet carburetors are used on California Light Duty truck with the Computer Command Control (CCC) system. The first letter "E" indicates the carburetor is a part of the CCC system. The third letter, if "E", indicates the carburetor is equipped with an electric choke.

Carburetor Identification Label. Scheme 23

Note. Original part number must be transferred from old float bowl if new float bowl is installed.

DESCRIPTION

The E4ME and E4MED carburetors are of 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 and E4MED carburetors use an electrically-actuated choke assembly, and 2 vacuum break diaphragm assemblies, the front and rear. Both models are used in conjunction with the Computer Command Control (CCC) System. The carburetors are 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.

The E4MED model carburetor incorporates a float bowl mounted dual capacity fuel pump and a combined mixture control/dual capacity pump solenoid assembly. When the engine is cold, more fuel is necessary to ensure a smooth transition from idle to part throttle. When the engine is warm, less fuel is required. The dual capacity pump is controlled by the coolant temperature sensor. When coolant temperature is approximately 170°F (77°C), a solenoid within the carburetor is energized, opening a by-pass valve. This lowers the capacity of the pump by about one-half.

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.

These carburetors 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.

MIXTURE CONTROL SOLENOID PLUNGER TRAVEL

Note. Mixture control solenoid plunger travel should be checked before proceeding with any carburetor adjustments or disassembly.

1. Remove air cleaner and gasket. Insert Float Gauge (J-34935-1) down "D" shaped vent hole. Lightly press down on float gauge and release. Ensure that gauge moves freely and does not bind.
2. With float gauge released, read gauge at eye level and record reading of gauge mark that lines up with top upper edge of air horn casting. Lightly press down on gauge until plunger is bottomed out. Read and record reading of gauge mark that lines up with top upper edge of air horn casting.
3. Subtract float gauge "UP" position from float gauge "DOWN" position and record difference of total plunger travel. If reading is within specification, adjust idle air bleed valve. See appropriate TUNE-UP article.
4. If plunger total travel is not between 2/32" and 6/32", adjust mixture control solenoid plunger travel. See «ADJUSTMENTS»(/chevrolet/pickup-c10/1985-1986/remont/testing-diagnostics/#carburetor-rochester-e4me-e4med-4-bbl__adjustments) in this article.

ADJUSTMENTS

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

CHOKE VALVE ANGLE GAUGE

Manufacturer recommends that some carburetor adjustments be performed using a Choke Valve Angle Gauge (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.

1. With choke valve closed, place angle gauge magnet squarely on choke valve.
2. Rotate degree scale on angle gauge so that 0° mark is opposite pointer.
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 appropriate adjustment procedure.

Choke Valve Angle Gauge. Scheme 24

Note. This gauge must be used to perform some adjustments.

FLOAT LEVEL (WET SETTING)

Note. This is an on-vehicle adjustment.

1. With engine running at idle and choke wide open, carefully insert Float Gauge (J-34935-1) into vent slot or vent hole (next to air cleaner mounting stud) in air horn. Allow gauge to float freely. see scheme 3
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.

FLOAT LEVEL (DRY SETTING)

1. Remove air horn and gasket. Remove solenoid plunger, metering rod, and float bowl insert.
2. If it is necessary to remove lean mixture solenoid adjustment screw, count and record the number of turns it takes to slightly bottom screw using Wrench (J-28696-10).
3. Attach Adjustment Base (J-34817-1) to float bowl. Place Float Weight (J-34817-3) in base with contact pin resting on outer edge of float lever. Using Float Adjustment Gauge (J-9789-90), measure distance from top of casting to top of float at point 3/16" from large end of float.
4. If float level is more than 1/16" from specification, use Float Lever Bender (J-34817-15) to bend float lever up or down. Remove bender and check float level. Repeat procedure until it is within specification.
5. Check float alignment. Return solenoid lean mixture adjustment screw to original position (turns recorded during removal). Reassemble carburetor.

Dry Float Level Adjustment. Scheme 25

Note. This is a preliminary adjustment only. It is required to ensure that mixture control solenoid 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.

Scheme 26

1. Remove air horn, solenoid adjustment screw, rich limit stop, mixture control solenoid plunger, primary metering rods with springs. plastic filler block and mixture control solenoid. (Scheme 26)
2. Inspect mixture control solenoid bore or plunger wear or sticking. Check metering rods for wrong part number, sticking or improperly installed springs. Check for foreign material in jets. (Scheme 26): Removing Mixture Control Solenoid
3. Install Mixture Control Solenoid Gauge (J-33815-1) over the throttle side metering jet rod guide. Temporarily install solenoid adjustment screw spring, mixture control solenoid, plunger, rich limit stop, and solenoid adjustment screw. see scheme 6
4. Hold solenoid plunger "DOWN" with light finger pressure and as close to plunger shaft as possible. Using Wrench (J-28696-10), slowly turn solenoid adjustment screw clockwise until plunger contacts gauge. (Scheme 27)
5. Slowly turn solenoid adjustment screw counterclockwise until the plunger breaks contact with gauge. The adjustment is correct when solenoid plunger is contacting both the solenoid stop and gauge. see scheme 6: Installing Mixture Control Solenoid Gauge
6. Note position of "T" handle on wrench. Count and record the number of turns required to turn the solenoid adjustment screw clockwise until the solenoid bottoms out against float bowl.
7. Remove solenoid adjustment screw, rich limit stop, mixture control solenoid, plunger, solenoid adjustment screw spring, and gauge. Install solenoid adjustment screw spring, mixture control solenoid, and plastic filler block. Install primary metering rods and springs.
8. Install mixture control solenoid plunger, rich limit stop, and solenoid adjustment screw. Using wrench, turn solenoid adjustment screw clockwise until mixture control solenoid bottoms out against float bowl.
9. Turn wrench counterclockwise the exact number of turns recorded in step 6. Install new air horn gasket and install air horn on carburetor. Tighten carburetor screws using tightening sequence. (Scheme 40)

Adjusting Mixture Control Solenoid. Scheme 27

SOLENOID RICH MIXTURE STOP SCREW (BENCH ADJUSTMENT)

Note. This is a preliminary adjustment only. It is required to ensure that solenoid 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 mixture control solenoid plunger travel properly set and air horn installed, insert Float Gauge (J-34935-1) in vertical "D" shaped vent hole in air horn casting.
2. With 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. see scheme 8: Solenoid Rich Mixture Stop Screw Bench Adjustment
3. Subtract the two readings taken in step 2. This difference is the total solenoid travel. Using Wrench (J-28696-10), turn rich mixture stop screw until total solenoid travel (difference between readings) is 4/32". see scheme 8
4. After adjustment, install lean mixture screw and solenoid rich mixture stop screw plugs. Plugs must be installed to seal settings and to prevent fuel vapor loss. (Scheme 28)

Installing Lean Mixture & Solenoid Rich Mixture Stop Screw Plugs. Scheme 28

IDLE MIXTURE NEEDLES & AIR BLEED VALVE (BENCH ADJUSTMENTS)

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. Before adjusting idle mixture needles ensure that air horn properly installed. Lightly seat idle mixture needles, then 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 air bleed valve, insert idle Air Bleed Valve Gauge (J-33815-2) in throttle side "D" shaped vent hole of air horn casting. Upper end of tool should be positioned over cavity next to valve. (Scheme 29)
5. Lightly push down on gauge so that solenoid plunger is against solenoid stop. Adjust idle air bleed valve so that gauge will pivot over and just contact top of air bleed valve. (Scheme 29) Install, adjust and plug all screws to restore tamper-resistant design.

Idle Mixture Needles & Air Bleed Valve Adjustments. Scheme 29

AIR VALVE SPRING

1. Use a 3/32" 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 30) Tighten lock screw. Apply lithium base grease to lubricate contact area.

Air Valve Spring Adjustment. Scheme 30

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 under OVERHAUL in this article.

1. Remove retaining rivets. Remove choke cover and coil assembly. Position fast idle speed cam follower on high step of fast idle cam. Push up (counterclockwise) on choke coil tang to close choke valve. (Scheme 31)
2. Insert a.120" drill or pin gauge in hole provided in choke housing. Lower edge of choke lever inside housing should just touch drill or pin gauge. To adjust lever, bend choke rod. (Scheme 31)

Note. 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.

Choke Coil Lever Adjustment. Scheme 31

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 . 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 32)
3. To adjust rod, bend tang on fast idle cam until bubble of choke valve angle gauge is centered.

Choke Rod (Fast Idle Cam) Adjustment. Scheme 32

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 withh CHOKE VALVE ANGLE GAUGE . 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 33)
3. 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. Scheme 33

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. 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. see scheme 15
3. 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. Adjustment is correct when bubble of choke valve angle gauge is centered.
4. 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.

AIR VALVE ROD (FRONT)

1. Using an outside vacuum source of at least 18 in. Hg, seat primary (front) vacuum break diaphragm. (Scheme 34) Plug air bleed hole (if equipped) with 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.025" drill or pin gauge. (Scheme 34)
3. Bend rod to adjust clearance in slot to.025" with vacuum still applied. Remove tape and reconnect vacuum hose to diaphragm.

Air Valve Rod Adjustment (Front). Scheme 34

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 35)
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). Scheme 35

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 under OVERHAUL in this article. 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. 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 36)
2. Hold throttle lever in wide open position. To adjust unloader, bend choke unloader tang on fast idle lever until bubble of choke valve angle gauge is centered. Remove gauge.

Choke Unloader Adjustment. Scheme 36

Lockout Lever Side Clearance

Hold choke valve and throttle valves completely closed. (Scheme 37) Measure side clearance between pin and lockout lever. Specified lockout lever side clearance is.015". To adjust, bend pin.

Lockout Lever Opening Clearance

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

Secondary Throttle Valve Lockout Adjustment. Scheme 37

DISASSEMBLY

Note. Before performing any service on carburetor, it is essential that carburetor be placed on Holding Fixture (J-9789-118) to prevent damage 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.
2. Remove choke link from lower lever inside float bowl casting. Remove link by holding lower lever outward with small screwdriver and twisting link counterclockwise.
3. 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 removed from hanger by rotating ends out of holes in end of hanger.
4. Remove pump link retainer, then remove link 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. NOTE: DO NOT attempt to remove pump lever from air horn as damage to air horn could result.
5. 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 tubes.
6. 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.
7. Invert air horn. Using a small screwdriver, remove staking that holds TPS seal and pump plunger stem seal retainers. Use care when removing retainers and seals to prevent damage to air horn casting. Discard retainers and seals.
8. Using a small punch, drive the solenoid adjustment screw plug out of air horn. Discard plug. Further disassembly of air horn is not required for cleaning purposes.
9. 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.
10. 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 cleaning and servicing unless carburetor or mixture control solenoid has been diagnosed as cause of poor engine performance.

Air Bleed Valve

1. 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.
2. Drill off rivet heads of bleed valve cover with a 7/64" 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.
3. After removing cover, check for letter identification on top of idle air bleed valve. This will determine the necessary adjustment procedure after reassembly.
4. 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 air horn gasket by lifting off of dowel locating pins, and from under and around solenoid plunger. Discard gasket. Remove pump plunger and return spring from pump well.
2. Remove mixture control/dual capacity pump solenoid assembly as follows: Remove solenoid attaching screw. DO NOT remove solenoid connector from float bowl at this time.
3. Using Wrench (J-28696-10), remove mixture control solenoid adjustment screw, solenoid plunger, and solenoid plunger rich limit stop as an assembly. DO NOT remove plunger return spring or connector wires from solenoid bodies. The mixture control solenoid, plunger and connectors, are serviced as an assembly.
4. Remove plastic insert from top of mixture control assembly. Carefully lift each metering rod out of its metering jet guide. Ensure that return spring is removed with each rod.
5. Remove rubber gasket from top of solenoid connector. Discard gasket. Remove solenoid adjusting screw tension spring from float bowl, next to float hanger pin.
6. Remove float assembly and float needle by pulling up on retaining pin. Using Seat Remover (J-22769), remove needle, seat and gasket. Remove large mixture control solenoid tension spring from boss on bottom of float bowl, located between metering jets.
7. Remove staking holding TPS in bowl as follows: Protect gasket surface by laying a flat piece of metal across casting. Using a small screwdriver, lightly depress and hold TPS down against spring tension.
8. Carefully remove staking from around TPS by prying upward with a small chisel against the metal piece (not bowl casting). Push up from bottom on electrical connector and remove TPS and connector assembly from bowl. Use care not to damage sensor.
9. Remove spring from bottom of TPS well in float bowl. If necessary, remove primary main metering jets using Metering Jet Remover (J-28696-4). Use care not to damage metering rod guide upper areas. NOTE: DO NOT attempt to remove secondary metering jets. Secondary jets are permanent and if damaged, float bowl must be replaced.
10. On E4MED carburetor, use Accelerator Bypass Valve Wrench (J-34928) to remove accelerator bypass valve and gasket. Remove pump discharge ball retainer.
11. Invert bowl and catch discharge ball as it falls. Remove secondary air baffle, if replacement is required. If necessary, remove pump well fill slot baffle.
12. Remove hose from rear vacuum break assembly. Remove 2 attaching screws from float bowl. Remove rear vacuum break and bracket assembly. Rotate assembly to remove vacuum break link from slot in plunger.
13. Remove fuel inlet nut, gasket, filter assembly, and spring. Discard filter assembly and gasket. Remove 3 throttle body-to-bowl attaching screws and lock washers. Remove throttle body assembly. Remove throttle body-to-bowl insulator gasket.

Choke Cover

1. Align a 5/32" 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.
2. Remove retaining screw and washer from inside choke housing. Slide choke housing away from float bowl. Remove secondary throttle valve lockout lever from float bowl. Invert bowl and remove lower choke lever from inside bowl cavity.
3. To disassemble intermediate choke shaft from from choke housing, remove coil lever retaining screw from end of choke shaft. Remove thermostatic coil lever from flats on choke shaft.
4. Slide intermediate choke shaft out of choke housing. Remove fast idle cam from choke shaft. Remove cup seal from float bowl insert. DO NOT remove insert.

Exploded View of Rochester Model E4ME & E4MED 4-Barrel Carburetor. Scheme 38

Throttle Body

Remove accelerator pump link from throttle lever by rotating link until tang on link 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, proceed as follows

Idle Mixture Needle Plugs

1. Turn throttle body over, and make 2 parallel cuts in throttle body using a small hacksaw, cutting on each side of idle mixture needle plugs. 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.
2. 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. (Scheme 39)
3. 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 plug. When removing or installing needles, refer to appropriate TUNE-UP article.

Idle Mixture Needle Plug Removal. Scheme 39

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.
5. If float bowl needs replacement, inspect for letters "MW" (next to fuel inlet) on casting. These letters indicate a machined pump well, and determine type of pump needed. Replacement float bowl also must have "MW" letters.

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. After assembly perform mixture control solenoid travel adjustment. See «ADJUSTMENTS»(/chevrolet/pickup-c10/1985-1986/remont/testing-diagnostics/#carburetor-rochester-e4me-e4med-4-bbl__adjustments) in this article.
5. When installing idle air bleed valve, lightly coat 2 new "O" ring seals with automatic transmission fluid. Thick seal goes in upper groove and thin seal goes on lower groove. Adjust air bleed valve. See «ADJUSTMENTS»(/chevrolet/pickup-c10/1985-1986/remont/testing-diagnostics/#carburetor-rochester-e4me-e4med-4-bbl__adjustments) in this article. 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: 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. (Scheme 40)

Air Horn Screw Tightening Sequence. Scheme 40

SPECIFICATIONS

CARBURETOR ADJUSTMENT SPECIFICATIONS

See also:
• ADJUSTMENTS
• OVERHAUL
• CHOKE VALVE ANGLE GAUGE