Carburetor - Holley 5220 & 6520 2-bbl Dodge Caravan I

COMPONENT TESTING

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

APPLICATION

HOLLEY CARBURETOR NO.

IDENTIFICATION

Carburetor identification number may be found stamped on the rear of throttle body. A mirror is required to read the number when carburetor is installed on vehicle.

DESCRIPTION

Carburetor models 5220 and 6520 are 2-stage, 2-venturi type. Primary venturi is smaller than secondary. Secondary stage is mechanically operated by linkage to primary and secondary throttle levers. Primary stage includes curb idle, accelerator pump idle transfer, main metering and power enrichment systems.

Secondary stage includes main metering and power enrichment systems. A single fuel bowl supplies fuel for both stages. Carburetor is equipped with an electric automatic choke which has a 2-stage bi-metal heating element.

On 6520 model carburetors there is also an oxygen feedback solenoid that is responsive to the oxygen sensor.

ADJUSTMENT

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

FLOAT LEVEL

1. Remove air horn and gasket. Turn air horn upside-down. Allow weight of float to press down against float needle valve. (Scheme 18) Measure float level clearance between top of float and air horn gasket surface.
2. Make sure float tang still rests on float needle when clearance is checked. To adjust, bend tang that contacts float needle. DO NOT apply pressure to needle while checking or changing adjustment.

Scheme 18

FLOAT DROP

With air horn and gasket removed, turn air horn right-side-up. Using a "T" scale, measure float drop from air horn gasket surface to bottom of float. (Scheme 19) To adjust, bend float tang on float arm that contacts fuel inlet needle seat boss.

Scheme 19

CHOKE VACUUM KICK

1. Open throttle and close choke. Close throttle to trap fast idle cam in closed choke position. Disconnect vacuum hose at choke vacuum diaphragm. Connect hand-held vacuum pump and apply 15 in. Hg of vacuum.
2. Apply slight closing pressure to choke valve without bending linkage. An internal spring within choke system will compress to stop position.
3. Using a drill or pin gauge, measure clearance between upper edge of choke valve and primary air horn wall. Adjust by rotating Allen head screw in center of diaphragm housing. (Scheme 20)

Scheme 20

DISASSEMBLY

1. Disconnect and remove choke operating rod and seal. Remove 2 throttle kicker solenoid retaining screws, bracket, and solenoid (if equipped). Remove vacuum secondary control solenoid and filter assembly.
2. Remove wiring clip from top of carburetor. On model 6520, remove 2 oxygen feedback solenoid screws and gently lift solenoid from air horn. On all models, remove clip securing vacuum secondary control rod to link. Remove control mounting screws (3) and vacuum diaphragm.
3. Mark location of 2 wide open throttle cut-out switch mounting screws for reassembly reference. Remove screws and cut-out switch. Remove harness screws and retaining clip.
4. Remove 5 air horn mounting screws and separate air horn from main body. Remove float hinge pin, float, and float inlet needle. Remove fuel inlet seat and gasket.
5. Remove secondary and primary main metering jets, high speed bleeds, and main well tubes. Note size and position of each part for reassembly reference. Remove discharge nozzle screw, nozzle, and gasket.
6. Turn carburetor upside-down and catch accelerator pump discharge weight ball and check ball. Both balls are same size. Remove 4 accelerator pump cover screws, cover, pump diaphragm, and spring.
7. Note position of accelerator pump arm pivot pin. If pivot pin is removed, it must be installed in its original position. Remove 3 choke diaphragm cover screws. Remove cover and spring.
8. Rotate choke shaft and lever assembly counterclockwise. Rotate choke diaphragm assembly clockwise and remove from housing.
9. Mount carburetor in padded vise to access idle mixture screw plug (located below choke housing). Center punch casting at a point 1/4" away from end of mixture screw housing.
10. Drill a 3/16" hole in casting at punch mark. Pry out plug and save for reassembly. Count number of turns required to lightly seat mixture screw. Remove idle mixture screw and spring.

Scheme 21

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 rubber or plastic parts in cleaner, particularly choke diaphragm and heater. These parts are best cleaned with a clean cloth and/or soft brush.
3. DO NOT use drills or wire to clean jets or other passages.
4. If cleaner manufacturer recommends rinsing with water, hot water will give best results.
5. Blow out all passages with dry, compressed air.

REASSEMBLY

1. If entire choke assembly was removed, position on carburetor and install 3 retaining screws. If choke diaphragm was removed, rotate choke shaft counterclockwise. Insert diaphragm with a clockwise motion.
2. Position spring and cover over diaphragm and install retaining screws. Ensure that fast idle link has been properly installed. Install accelerator pump spring, diaphragm cover, and screws.
3. Install accelerator pump discharge check ball. Fill fuel bowl with clean fuel to check ball and seat operation. Hold discharge check ball down with small brass rod. Place accelerator pump assembly in well and operate by hand.
4. If no resistance is felt, check ball is leaking. Using a small drift punch, lightly tap ball against seat to form a new seal. Remove old check ball and discard. Install new check ball.
5. Perform fuel leak test again. If there is still no resistance felt, main body must be replaced. If resistance is felt, check ball is seating correctly. Install new gaskets, discharge nozzle, and screw.
6. Install primary and secondary main well tubes, high speed bleeds, and main metering jets. Primary main metering jet will have a smaller number stamped on it. Install needle and seat assembly. Install float, check float level, and float drop.
7. Position gasket on air horn. Install choke rod seal and operating rod. Carefully install air horn on main body. Install new choke operating rod retainers on choke shaft and fast idle cam, and then connect choke operating rod.
8. Install and tighten 5 air horn screws to 30 INCH lbs. (3 N.m). Install and tighten idle stop solenoid screws. Install throttle kicker solenoid and tighten retaining screws. Install wide open throttle cut-out switch.
9. Move switch so that A/C clutch circuit is open at 10 degrees before wide open throttle position. On model 6250, install new oxygen feedback solenoid gasket on air horn. Install new "O" ring on oxygen feedback solenoid.
10. Lightly lubricate "O" ring with white grease and carefully install solenoid in carburetor. Install mounting screws and route wiring through clamp. Install vacuum secondary control diaphragm and solenoid. Install and tighten wire clip screws.

SPECIFICATIONS

CARBURETOR ADJUSTMENT SPECIFICATIONS