Carburetor - Holley 4180-c 4-bbl Ford RV Cutaway E350

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

The identification tag is attached to the carburetor. The tag contains the part number prefix and suffix. Basic part number for all carburetors is 9510. A design change code (if any) is stamped on the tag. An assembly date code (year, month and day) is also stamped on the tag.

DESCRIPTION

The Holley 4180-C carburetor is a downdraft, 2-stage carburetor. It has 2 separate stages: one supplying air/fuel mixture throughout the entire range of the engine operation (primary stage); the other functioning only when a greater supply of air/fuel is needed (secondary stage).

The primary stage (front section) contains a fuel bowl, metering block, and accelerator pump assembly. The secondary stage (rear section) contains a fuel bowl, metering body, and a secondary throttle operating diaphragm assembly.

This carburetor has 5 main systems: idle, main meter, secondary throttle, power enrichment and accelerating pump. In addition to these basic systems, it is also equipped with fuel inlet and automatic choke systems.

The 4180-C used in Federal 5.8L engine (over 8500 lbs. GVW) and on California 7.5L engines incorporate a "modulated power system". This system ensures power valve operation (opening) during heavy acceleration at times when manifold vacuum may increase beyond the point where the power valve would begin to close.

A 7/16" diameter non-restricted external fuel bowl vent is used on all 4180-C carburetors. Vent tubes are located on top of the primary and secondary fuel bowls. The vent outlet connects through a purge hose to the fuel evaporator canister.

ADJUSTMENT

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

FLOAT LEVEL - DRY

1. Remove fuel bowls and float assemblies. Hold bowls upside-down. Float is adjusted correctly if top of float is parallel with float bowl. (Scheme 1) To adjust, loosen lock screw and turn adjustment nut until float is parallel.
2. Dry float adjustment is only a preliminary fuel level adjustment. Final (wet) fuel level adjustment must be performed with carburetor installed on vehicle. See «FLOAT LEVEL - WET»(/ford/rv-cutaway-e350/1987-1987/remont/testing-diagnostics/#carburetor-holley-4180-c-4-bbl__float-level-wet).

Scheme 1

FLOAT LEVEL - WET

1. Start engine until it reaches normal operating temperature. Place vehicle on a flat surface. Remove air cleaner (if installed). Run engine at 1000 RPM for 30 seconds to stabilize fuel in carburetor.
2. Stop engine and remove sight plug from primary side fuel bowl. Check fuel level. Fuel level should be at bottom of sight plug hole. If fuel spills when plug is removed, lower fuel level by turning adjustment nut clockwise.
3. If fuel level is below sight plug hole, raise fuel level by turning adjustment nut counterclockwise. Turning adjustment nut 5/32" (4 mm) will change fuel level about 1/32" (.79 mm).
4. Tighten lock screw and install sight plug. Start and run engine at 1000 RPM for 30 seconds. Stop engine, remove sight plug and check fuel level. If necessary, adjust fuel level.
5. If fuel level is at bottom of sight plug, install sight plug using a new plug gasket. Repeat procedure for secondary fuel bowl. Secondary throttle MUST be used to stabilize fuel level in secondary fuel bowl.

ACCELERATOR PUMP LEVER

1. Place throttle valves in wide open position. Using a feeler gauge, measure clearance between lever adjustment screw head and pump arm with pump arm manually depressed. (Scheme 2)
2. To adjust, loosen adjustment screw lock nut. Turn adjustment screw in to increase clearance, and out to decrease clearance. Each 1/2 turn of adjustment screw equals.015" (.38 mm). Tighten lock nut.

Scheme 2

ACCELERATOR PUMP STROKE

Accelerator pump stroke has been preset at factory. Setting should not be changed. If original setting has been changed, adjust as follows

Check that plastic accelerator pump cam is aligned with correct hole (top or bottom) in throttle lever. Plastic accelerator pump cam is located behind throttle lever. If not aligned with correct hole, remove screw. Reposition in correct hole. Install and tighten screw.

SECONDARY THROTTLE VALVES

Hold secondary throttle valves closed. Turn secondary throttle shaft stop screw out until secondary throttle valves seat in throttle bores. Turn screw in until it just contacts secondary throttle valve lever. Turn screw in an additional 3/8" (10 mm) turn.

CHOKE PULL-DOWN

1. Place carburetor on a stand which will allow access to pull-down diaphragm vacuum passage on underside of throttle body. (Scheme 3) Mark choke cap and choke housing for adjustment reference.
2. Using a hacksaw, carefully cut a slot in head of choke cap breakaway screws. Using a screwdriver, remove breakaway screws and conventional screw. Remove retainer, choke cap, and gasket.
3. Temporarily install choke cap and gasket. Line up marks made prior to disassembly and rotate cap 90 degrees counterclockwise from this position. Secure choke cap with one screw.
4. With choke plate fully closed, actuate choke pull-down diaphragm by applying at least 17 in. Hg of vacuum. Using a drill or gauge, check clearance between lower edge of choke plate and air horn wall.
5. If adjustment is required, carefully remove diaphragm adjustment screw cap with a small punch or screwdriver. (Scheme 3) Using a 5/46" Allen wrench, turn screw clockwise to decrease clearance and counterclockwise to increase clearance.
6. Maintain vacuum applied to diaphragm during adjustment. Cycle vacuum from zero to 17 in. Hg to verify adjustment. When adjustment is correct, apply RTV sealant to adjustment screw cavity and check fast idle cam position.

Scheme 3

FAST IDLE CAM POSITION

1. Using a hacksaw, carefully cut a slot in head of choke cap breakaway screws. Using a screwdriver, remove breakaway screws and conventional screw. Remove retainer, choke cap, and gasket.
2. Temporarily install choke cap and gasket. Line up marks made prior to disassembly and rotate cap 90 degrees counterclockwise from this position. Secure choke cap with one screw.
3. Apply vacuum to choke pull-down diaphragm and cycle throttle. Fast idle speed screw should rest on top step of fast idle cam with throttle closed. (Scheme 4)
4. If adjustment is required, turn adjustment screw clockwise to position fast idle screw higher on second step. Turn counterclockwise to position screw lower on second step.
5. Remove temporary choke cap and gasket. Install original locking gasket, choke cap, and retainer. Secure choke assembly with 2 breakaway screws and conventional screw.

Scheme 4

CHOKE UNLOADER

Hold throttle valves wide open. Apply light closing pressure on choke valve. (Scheme 4) Measure choke unloader clearance between lower edge of choke valve and air horn wall. To adjust, bend pawl on fast idle cam lever.

Scheme 5

1. Remove fuel bowl and gasket. Remove metering block and gasket. Discard gaskets. Remove pump transfer tube from main housing or metering block. Discard "O" rings. Remove fuel line tube and discard "O" ring.
2. Using a jet wrench, remove main jets from primary metering block. Using a socket wrench, remove power valve and gasket. Note and record power valve I.D. number (on base of valve) for reassembly reference.
3. Remove fuel level adjustment lock screw and gasket. Turn adjustment nut counterclockwise to remove fuel inlet needle, seat, nut, and gasket. DO NOT disassemble needle and seat. They are replaced as an assembly only.
4. Using needle nose pliers, remove float shaft retaining clip. Slide float off shaft and remove spring from float. Remove baffle plate from fuel bowl. Remove fuel level sight plug and gasket.
5. Remove fuel inlet fitting, gasket, and filter. Invert fuel bowl and remove accelerator pump cover, diaphragm, and spring. DO NOT remove accelerator pump inlet check ball. Check ball is not a serviceable item.
6. Remove secondary fuel bowl. Using a clutch type screwdriver, remove metering block screws. Remove metering block, plate, and gaskets. Discard gaskets. Remove fuel level adjustment lock screw and gasket.
7. Turn adjustment nut counterclockwise to remove fuel inlet needle, seat, nut, and gasket. DO NOT disassemble needle and seat. They are replaced as an assembly only.
8. Using needle nose pliers, remove float shaft retaining clip. Slide float off shaft and remove spring from float. Remove baffle plate from fuel bowl. Remove fuel level sight plug and gasket.
9. Remove air cleaner stud. Remove secondary diaphragm link "E" clip. Invert carburetor and remove throttle body retaining screws and lock washers. Lift off throttle body and discard throttle body gasket.
10. Using a hacksaw, carefully cut a slot in head of choke cap breakaway screws. Using a screwdriver, remove breakaway screws and conventional screw. Remove retainer, choke cap, and gasket.
11. Remove 3 choke housing screws and separate housing from main body by pushing choke rod out of retainer on choke housing shaft lever. Remove choke housing shaft nut, washer, spacer, lever fast idle cam spring, spring perch, and fast idle cam.
12. Remove overtravel spring and choke housing shaft. Remove choke diaphragm cover screws and separate diaphragm and spring from cover. Slide diaphragm and shaft assembly out as far as it will go, then remove choke modulator spring retaining clip.
13. Remove choke modulator spring, spring seat, and spring perch. Slide choke diaphragm assembly out of choke housing, then remove nylon choke modulator bushing from choke housing.
14. Snap out choke rod from choke shaft lever retainer. Pull choke rod up to remove it from dust seal. Remove choke plate from choke shaft and slide shaft and lever out of air horn. NOTE: Retaining screws are staked to choke shaft. If screw tips are flared excessively, file off flared portion to avoid damage to threads in choke shaft. DO NOT damage choke shaft or venturi.
15. Remove 3 screws and then remove secondary diaphragm housing and "O" ring from main body. Remove diaphragm housing cover. Remove spring, diaphragm, and vacuum check ball from housing.
16. Remove accelerator pump discharge nozzle screw. Lift off discharge nozzle and gaskets. Invert main body and catch accelerator pump discharge check ball (or needle) as it falls out of bore. DO NOT disassemble throttle body. If worn or damaged, replace as an assembly.

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.
3. DO NOT use wire, drill or any hard parts to clean passages and orifices in carburetor.
4. Remove any residue after cleaning by rinsing components in suitable solvent.
5. Blow out all passages with dry compressed air.

REASSEMBLY

1. To assemble, reverse disassembly procedure. Make sure that new gaskets fit correctly and that all holes and slots are punched through and correctly located.
2. Drop accelerator pump discharge check ball into bore. Lightly seat check ball with a brass drift and light hammer. Pump discharge gaskets, nozzle, and screw must be installed before any other parts are installed on main body.
3. Using a flat punch, stake nozzle screw into position. Apply petroleum jelly to all "O" rings before installation. Make sure to install correct power valve. Install secondary diaphragm housing before installing choke housing. Tighten choke diaphragm cover screws to 13-17 INCH lbs. (1.5-1.9 N.m)
4. Install and tighten choke housing screws to 20-30 INCH lbs. (2.3-3.4 N.m). When installing float spring, ensure that float spring is between ridges on boss on floor of fuel bowl. Using needle-nose pliers, install float "E" clip.

SPECIFICATIONS

CARBURETOR ADJUSTMENT SPECIFICATIONS

See also:
• FLOAT LEVEL - WET