Carburetor - Holley 6145 1-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 part number is stamped on side of carburetor, next to solenoid bracket. Carburetor may also be identified by tag attached to carburetor.

DESCRIPTION

The Holley model 6145 is an electronic feedback carburetor. The carburetor is designed to maintain an air/fuel ratio within specified limits to allow the catalytic converter to operate effectively. The air/fuel ratio is controlled by the Spark Control Computer.

The carburetor includes 4 basic fuel metering systems: idle, main metering, accelerator and power enrichment. In addition, fuel inlet and choke systems are used.

ADJUSTMENTS

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

FLOAT LEVEL

With air horn removed, turn main body upside-down with gasket installed. Hold a straightedge across main body, over floats, at point farthest from fuel inlet. Floats should just contact straightedge. (Scheme 4) To adjust, bend float tang touching fuel inlet needle.

Scheme 4

CHOKE VACUUM KICK

1. Open throttle and close choke. Close throttle to trap fast idle cam in closed choke position. (Scheme 5) Disconnect vacuum hose from choke vacuum diaphragm. Connect hand-held vacuum pump to diaphragm and apply at least 15 in. Hg vacuum.
2. Apply light finger pressure on choke shaft lever to compress spring in diaphragm stem without distorting linkage. Diaphragm stem reaches a stop as spring is compressed.
3. Measure choke vacuum kick specified clearance between upper edge of choke valve and air horn wall. (Scheme 5) To adjust, bend diaphragm link at "U" bend. Check all linkage for freedom of movement. Remove vacuum pump and install vacuum hose.

Scheme 5

FAST IDLE CAM POSITION

1. Position fast idle speed screw on second step of fast idle cam. Hold choke valve toward closed position with light pressure on choke shaft lever. (Scheme 6)
2. Using specified drill or pin gauge, measure fast idle cam specified clearance between upper edge of choke valve and air horn wall. To adjust, bend fast idle link rod at angle.

Scheme 6

CHOKE UNLOADER

1. Hold throttle valves in wide open position. Hold choke valve toward closed choke position by applying light closing pressure to choke lever. (Scheme 7)
2. Using specified drill or pin gauge, measure clearance between top of choke valve and air horn wall at throttle lever side. To adjust, bend tang on throttle lever.

Scheme 7

ACCELERATOR PUMP STROKE

1. Place throttle lever in curb idle position. Make sure accelerator pump rod link is installed in correct hole in throttle lever. (Scheme 8)
2. Measure length of pump operating link from center of rod in throttle lever to center of rod in accelerator pump arm. To adjust, bend accelerator pump rod at "U" bend.

Scheme 8

Scheme 9

1. Perform disassembly procedure with carburetor on stand to avoid damage to throttle valves. Remove wire retainer and bowl vent solenoid. Remove idle stop solenoid.
2. Remove fast idle cam retaining clip, fast idle cam, and link rod. Remove rod from fast idle cam. Remove choke vacuum diaphragm, link, and bracket assembly. Disconnect diaphragm rod from slot in choke lever.
3. Remove nut and washer from throttle shaft. Note position of rod in throttle lever and record hole used for reassembly reference. Remove screws and duty cycle (feedback) solenoid.
4. Remove air horn screws. Separate air horn from main body by tapping with a plastic hammer or screwdriver handle. DO NOT pry off. Lift air horn straight up until vacuum piston stem, accelerator pump and main well tube are clear of main body.
5. Remove air horn gasket and clean gasket surface with cleaner. DO NOT use a metal gasket scraper. Use a nylon or hard plastic scraper as needed.
6. Remove accelerator pump rod retainer screw and retainer. Remove accelerator pump assembly retainer screw and pump assembly. Rotate pump rod as needed to remove from air horn. Remove pump rod grommet.
7. Power piston assembly retaining ring is staked in position. Carefully remove staking with sharp tool. Remove vacuum piston from air horn by depressing piston and allowing it to snap up against retaining ring. NOTE: DO NOT attempt to remove main well tube from air horn. Main well tube must be carefully blown out with compressed air from both sides of air horn.
8. Remove fuel inlet fitting valve assembly from main body. Remove and discard old gaskets. Remove float pivot pin retainer, pivot pin and float assembly. Turn main body upside down and catch pump discharge weight and ball as they fall out.
9. Remove main metering jet with Wrench (C-3748) or 3/8" wide flat screwdriver with good square blade. Carefully depress power valve needle with 3/8" wide screwdriver until screwdriver blade seats in slot in top of valve. Remove valve assembly. NOTE: Power valve assembly consists of needle, seat and spring. If replacement of any part is required, replace complete assembly. Service valve includes all components.
10. Remove 3 main body-to-throttle body screws and separate assemblies. Remove and discard gasket. Remove fast idle speed screw and spring from throttle body.
11. Remove idle mixture screw plug. (Scheme 9) To remove plug, center punch idle mixture screw housing 1/4" from end of housing. Drill through outer section of housing at punch mark with 3/16" drill.
12. Pry plug out of housing and save for reassembly. Turn mixture screw in until lightly seated, counting turns. Record for reassembly reference. Remove mixture screw and spring.

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. To assemble, reverse disassemble procedure. Use all new gaskets and seals. Ensure that gaskets fit correctly and that all holes and slots are punched through and properly aligned.
2. If excessive wear exists between throttle shaft and throttle body, throttle body assembly should be replaced. Manufacturer does not recommend installing a new shaft in old throttle body.
3. Inspect idle mixture screw. Tapered portion should be straight and smooth. Replace if excessively worn or grooved. Install mixture screw and spring in throttle body. Bottom screw lightly and back out number of turns recorded during disassembly.
4. Install new throttle body gasket on main body. Place throttle body in position and tighten 3 retaining screws to 30 INCH lbs. (3 N.m). Ensure that all staking has been removed from vacuum piston retainer cavity. Install power piston spring and piston in cylinder, install spring retainer and stake lightly in place.
5. Install accelerator pump discharge check ball and weight. Fill fuel bowl with clean fuel to check ball and seat operation. Hold ball and weight down with brass rod. Place accelerator pump assembly in well and operate by hand. If no resistance is felt, check ball is leaking.
6. Remove weight, leaving check ball in place. 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 and weight. Perform fuel leak test again.
7. If there is still no resistance felt, main body must be replaced. If resistance is felt, check ball is seating correctly. Remove check ball and weight.
8. Install accelerator pump, pump rod and rod retainer in air horn. Install power valve assembly in bottom of fuel bowl. Tighten securely. Ensure needle valve operates freely. Install main jet in main body.
9. Install float pin in main body. Place float assembly in float shaft cradle. Install float pin retainer. Check float alignment to ensure that float does not bind against main body casting.
10. Install new gasket on fuel inlet fitting. Install fitting in main body. Tighten securely. Check float level and adjust as needed. Insert check ball and weight into accelerator pump discharge well.
11. Position air horn gasket on air horn. Carefully install air horn on main body. Make sure accelerator pump cup is not damaged. Install 7 air horn screws and tighten alternately, in steps, to 30 INCH lbs. (3 N.m).
12. Install new duty cycle solenoid gasket on air horn. Install new "O" ring on solenoid. Lubricate lightly with petroleum jelly and carefully install solenoid in carburetor.
13. Install and tighten mounting screws securely. Route wire and tighten screw. Install fast idle cam and link. Install choke vacuum diaphragm, idle stop solenoid, and bowl vent solenoid.

SPECIFICATIONS

CARBURETOR ADJUSTMENT SPECIFICATIONS