Carburetor - Holley 6520 2-bbl Dodge Aries I

COMPONENT TESTING

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

APPLICATION

CHRYSLER CORP.CARBURETOR NO.

IDENTIFICATION

Carburetor part number or identification number is either stamped on fuel bowl assembly, throttle body flange, or on a metal tag attached to carburetor.

DESCRIPTION

The Holley 6520 carburetors are "staged" dual venturi, electronic feedback carburetors. The primary side contains a float system, pump system and choke system.

The secondary side contains a secondary main metering and power system. Both primary and secondary fuel is provided by a common fuel bowl. The main metering system is incorporated within the primary and secondary systems.

The primary metering system provides air/fuel mixture for normal engine operation. The air/fuel ratio is controlled by a mixture control solenoid. The solenoid is electronically controlled by the Spark Control Computer.

The secondary main metering circuit provides fuel for full power operation. The carburetors are equipped with diaphragm-type accelerator pumps to provide additional fuel for sudden acceleration. The carburetors are equipped with electric chokes to assist cold engine starts.

ELECTRIC CHOKE

Using a jumper wire, connect choke to battery positive terminal. Choke valve should fully open within 5 minutes when vehicle is parked inside garage. Remove jumper wire.

ADJUSTMENTS

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

FLOAT LEVEL

Remove air horn and turn air horn upside down. Allow weight of float to press down against float needle valve. (Scheme 6) Measure clearance between top of float and air horn gasket surface. Clearance can be checked using a drill or pin gauge. To adjust, bend float tang.

Note. DO NOT apply pressure to float needle while checking or changing adjustment.

Float Level Adjustment Bend tang to adjust. Scheme 6

Hold air horn right side up. Using a "T" scale, measure float drop from air horn gasket surface to lowest part of float. To adjust, bend float tang with a small screwdriver. Support float while applying pressure to tang.

CHOKE VACUUM BREAK

1. Open throttle, close choke, then close throttle to place fast idle cam in closed choke position. Connect a vacuum source to vacuum break diaphragm and apply 15 in. Hg of vacuum.
2. Close choke valve as far as possible to compress spring inside choke. Insert drill or gauge between top of choke valve and primary air horn wall. Adjust vacuum break by rotating Allen head screw inside diaphragm housing.

Choke Vacuum Break Adjustment Rotate Allen head screw in diaphragm housing to adjust. Scheme 7

DISASSEMBLY

1. Remove fuel inlet fitting and filter. Remove mixture control (oxygen feedback) solenoid by removing screws and lock washers. Remove retaining clips and choke operating rod.
2. Remove choke rod seal, solenoid, vacuum control valve and wiring clip. Remove clip securing vacuum control rod to link, vacuum control screws and vacuum control diaphragm. Mark location of wide open throttle cut-out switch and remove screws. Remove harness mounting screws and open retaining clip.
3. Remove screws from choke diaphragm, remove cover and spring. Rotate choke diaphragm assembly and remove from housing. Remove plug from cover (if used) and remove adjustment screw.
4. Remove accelerator pump cover screws, pump cover, diaphragm and return spring. Remove throttle position sensor plunger from pump housing.
5. Remove air horn screws, lock washers and air horn. Remove float pin, float and inlet needle. Remove needle seat and gasket. Remove primary high speed bleed restriction and main well tube. Note size of both high speed bleed restriction and tube.
6. Remove secondary high speed bleed restriction and main well tube. Note size of high speed bleed restriction and tube. Remove primary and secondary main metering jets and note size. Remove pump discharge nozzle, gasket, check ball(s) and spring.

MIXTURE SCREW PLUG REMOVAL

Remove air cleaner crossover, canister purge, and diverter valve vacuum hose from carburetor. Center punch a mark 1/4" from end of mixture screw housing. Drill through outer housing using 3/16" drill bit. Pry out concealment plug and save for installation.

CLEANING & INSPECTION

1. DO NOT immerse plastic or rubber parts in solvent. DO NOT immerse diaphragm assemblies or solenoid in solvent.
2. Blow out all passengers with compressed air. DO NOT use wire or drill bit to clean out carburetor orifices.
3. Inspect all parts for wear, cracks, nicks or burrs, and damage. Replace parts as necessary.
4. After cleaning with solvent, wash all parts in hot water and blow dry with compressed air.

REASSEMBLY

Reverse disassembly procedure to reassemble. Use new gaskets and seals. Make sure that gaskets fit correctly, and that all holes and slots are punched through and correctly located.

SPECIFICATIONS

CARBURETOR ADJUSTMENT SPECIFICATIONS