Tools and Equipment for Rebuilding a Holley Carburetor • Muscle Car DIY

Carburetor service requires a selection of conventional hand tools as well as a select number of specialty tools. Many specialty tools are available from Holley as well as popular aftermarket suppliers, such as Summit Racing and Jegs. Having all of the tools listed here prior to beginning service makes your work more efficient and less time-consuming. When a specialty tool is required to perform a procedure, don’t substitute a general tool because you may damage the components and parts. Before you begin, clean your workbench surface and make enough room to spread out all parts in an organized manner.

This Tech Tip is From the Full Book, HOLLEY CARBURETORS: HOW TO REBUILD. For a comprehensive guide on this entire subject you can visit this link:

LEARN MORE ABOUT THIS BOOK HERE

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Basic Hand Tools

To completely disassemble and reassemble your Holley carb, you need a variety of hand tools. Carburetors are sensitive components and made of aluminum so you need to use the right tool for the job. In most cases, jets, screws, and other fasteners are installed with a light amount of torque, so be cautious and patient. Don’t force or overtorque any fasteners on the carburetor because you can easily damage vital components.

Resting a carburetor directly onto a workbench without raised fixtures can possibly result in bending linkages if excess downward pressure is applied during disassembly or assembly. Any carburetor should be properly secured and raised off of the work surface during any off-vehicle service.

Main jets have a slot that can be accommodated with a screwdriver, but a dedicated jet driver is preferred. Pictured here is Holley’s PN 26-68. The jet service tool’s handle is designed for a no-slip grip.

The driver tip includes a flat-blade that engages the jet, while a round pilot engages into the jet’s recess for a secure fit, eliminating accidental slipping and potential burring of the jet.

A 5/16-inch nut driver tool makes fuel-bowl screw service quick. During initial tightening, the small grip area of the tool helps to avoid over tightening.

A 5/16-inch nut driver tool makes fuel-bowl screw service quick. During initial tightening, the small grip area of the tool helps to avoid over tightening.

If you plan to perform precision carburetor service, it’s best to avoid guessing at fastener torque values and clamping loads. If you have the time, take advantage of a precision torque wrench to avoid leaks and mating surface distortion. A 1/4-inch drive torque wrench calibrated for 40 to 200 in-lbs is adequate. Do not use a torque wrench designed for foot-pound values!

Commonly, a 5/8-inch wrench and a flat-blade screwdriver are used to adjust floats. These are the tools that everyone has been using for decades, and there’s nothing wrong with this approach. A dedicated adjuster tool is simply more efficient, especially for racers who may need to perform service more often or in a hurry.

The benefits of using high-quality hand tools should be obvious. Cheap, bargain-basement tools may not be sized properly, and cheap chrome plating can flake off and contaminate your work. Although it’s certainly not necessary to buy the most expensive tools available, try to avoid extremely cheap, poor-quality offshore tools that may not have the required manufacturing tolerances and/or may not be hardened properly. Better-quality tools last longer, fit better, and reduce the potential for avoidable frustration.

Before disassembling a carburetor, take the time to clean your tools. Granted, you need to clean the parts anyway, but it just doesn’t make sense to add dirt, grit, and grease when you can avoid it. And certainly, before reassembly, it is absolutely mandatory to make sure that all tools are clean to avoid introducing contaminants to a clean carburetor. Cleaning your tools shouldn’t be limited to a quick exterior wipe-down. Properly clean all tool surfaces, including the inside of any socket, wrenches, ratchet or driver handles, screwdriver handles, shanks, and tips, etc. Also, take the time to inspect your tools for burrs or flaking plating.

Specialty Tools

Instead of using a flat-blade screwdriver for jet removal and installation, a dedicated jet removal tool is not only available but is highly recommended. An example is Holley’s jet tool (PN 26-68). It is specifically designed for jet service, offering a no-slip secure connection to a jet. Plus, it’s only used for jet servicing; it won’t become burred or otherwise damaged as often happens to a conventional screwdriver. It will always be ready for proper engagement to a jet when necessary.

Here’s a Holley Avenger carb mounted atop a set of plastic legs. This provides enough clearance to allow working the linkage without contacting the workbench surface.

The AED carburetor work fixture (PN 7920) can be benchmounted or secured to a bench vise. Two long T-handles secure the carb base to the fixture. The carb is positioned at a convenient working height. The AED carb fixture can be rotated 360 degrees for easy access to any service area. Here the carb is positioned 90 degrees.

This AED fixture, with the carb positioned upside-down, is solid and sturdy. The mounting arms pivot to align with one side of any carb’s baseplate.

Moroso’s cast-aluminum carb stand (PN 62070) has peg supports on each side, to accommodate either square-bore or spread-bore carburetors.

This is a very handy tool, especially for carburetor work. This example from Lisle is designed to pick up and hold small linkage rod clips.

When the thumb activated spring-loaded head is pressed, a small angled probe protrudes from the tip, to engage a small clip. Once the clip has been grabbed, releasing the thumb button secures the clip, preventing it from flying out into no-man’s land.

Although a 5/8-inch box wrench and a flat-blade screwdriver can certainly be used to adjust the float on a Holley carburetor, a handy option is to use a dedicated float adjuster tool, such as this one from Willy’s Carburetors.

The head is installed, capturing the power valve. During testing, an open passage allows you to observe valve movement as vacuum is applied to the tool.

This Tech Tip is From the Full Book, HOLLEY CARBURETORS: HOW TO REBUILD. For a comprehensive guide on this entire subject you can visit this link:

LEARN MORE ABOUT THIS BOOK HERE

With the power valve installed in the tool, connect a hand-held vacuum pump and apply vacuum to test the power valve.

A jet card, made of aluminum and threaded to accept primary and secondary jets, is a must-have for anyone who experiments with jet sizes for performance tuning. This card, from AED, neatly stores and organizes as many as 44 jets. Dumping spare jets into an old coffee can simply isn’t a good idea.

If annular boosters are to be installed, AED offers an annular booster adapter (PN 6-74) that mounts to their installer tool, to accept an annular-style booster.

AED’s booster installer (PN 6070) allows replacement boosters to be installed and swedged into place in the main body.

Power-valve removal/installation tools are available designed specifically for power-valve engagement. One example is from Willy’s Carburetors (PN 3104). Because power valves have an internal diaphragm, diagnosing problems is easy with a simple power-valve tester tool. This tool has a removable head. Insert the power valve into the tool, install the head, and connect the head’s vacuum port to a hand-held vacuum tester. Power-valve testers are available from a variety of manufacturers.

In addition, dedicated float/ needle and seat adjustment tools are available that incorporate a nut driver and screwdriver in one tool. A 5/8-inch open-end or box wrench and a flat-blade screwdriver are commonly used, but this type of specialty tool is handy and designed specifically for this task.

For enthusiasts and racers who routinely experiment with different jet sizes, a dedicated jet card is a necessity. Aluminum cards that have threaded holes to store an array of jets are extremely handy and eliminate sorting through a pile of jets stored in a can. These jet cards are available from a variety of sources, including AED (PN 6020).

When bench servicing a carburetor, using a stable fixture raises the carb above the workbench surface, which provides better access to various areas of the carb, and allows movement of the linkage. Carburetor work fixtures are available in three basic designs. The simplest (and least expensive) is a set of four plastic “legs,” each of which snap into the carburetor baseplate’s four mounting bolt holes. Another design is a one-piece plastic, aluminum, or steel platform with four raised pegs that engage into the baseplate bolt holes. A third design is more complex and can be secured in a vise or bolted to a workbench. It allows the carb to be moved away from the workbench and allows you to pivot the carb during service.

Chemicals

Several chemicals and lubes are useful during the assembly of a carburetor and its components. Have these lubes on hand so the components are assembled accurately and with minimal stress. Carburetor cleaning solvent (such as CRC TYME-1) is required, and a 1- to 5-gallon bucket for soaking parts is useful. A can of carb cleaner from Gunk or another suitable brand is also needed. Vaseline is used for lubricating O-rings. Lithium grease is suitable for throttle linkages and high-tack adhesive is good for securing gaskets in place.

Drill Bits

A selection of small-diameter drill bits accommodates modifications (if you choose to modify and/ or experiment). Examples include enlarging main jet sizes during testing to determine what size jets to purchase, slightly enlarging idle air bleeds to lean the idle mixture, etc. Bear in mind that before using any drill bit to modify components, you must carefully measure the shank’s diameter with a micrometer to verify the diameter of the bit. Drill bits can be unmarked, misplaced in their cases, etc. Never use a bit unless you first measure its diameter.

Torque Wrench

Carburetors are precision assemblies. Undertightening or overtightening of various threaded fasteners can easily lead to leaks, mating surface warpage, and even cracking (see Chapter 7 for various torque values). “Guesstimate” tightening simply isn’t a reliable method, so you need a quality calibrated torque wrench designed for inch-pound values. Because the torque values involved in carburetor work are on the “light” side, a 1/4-inch-drive inch-pound torque wrench is the best choice. The most accurate styles include micrometer, click-type ratcheting, or dial torque wrenches. A torque wrench with a range of 40 to 200 in-lbs is adequate for carburetor work.

Torque wrenches must be handled and stored with care. They should be recalibrated about once each year, with service intervals based on wrench use. Torque wrenches that are used on a regular basis require recalibration more often. Recalibration services are relatively inexpensive and are available from specialty service shops and through the tool’s manufacturer.

Cleaning Chemicals

Don’t attempt to use just “any” solvent to clean disassembled carburetor parts. Buy a dedicated carburetor cleaner. These cleaners are available in spray cans and 1-gallon cans to 5-gallon buckets. Dedicated carburetor cleaner solvents are designed to remove varnish and other deposits.

To remove these deposits properly from exterior surfaces as well as small orifices and passages, it’s best to soak the parts in this cleaning solution. The length of time varies, depending on the strength of the solution and the amount of deposit buildup. Parts may require soaking anywhere from 10 minutes to as long as an hour. Try to avoid soaking for extended periods, such as overnight.

These solvents are extremely aggressive. Extended soaking can, depending on the specific solvent and the soak time, potentially oxidize the finish. If the surfaces appear white and “fuzzy” after soaking, try rinsing in undiluted vinegar, which may remove the surface oxidation residue.

If your cleaning basket isn’t large enough to accommodate all of the parts, either use two baskets or soak half of the parts for the recommended time and soak the remaining parts during a second soak phase. Do not “help” the cleaning process by using a stiff wire brush, which can scratch precision surfaces. Allow the chemical to do its job.

Do not soak an assembled carburetor. Once the carburetor has been completely disassembled, load all parts into a basket (to avoid losing small parts) and soak as a group. Do not soak rubber or elastomer items such as O-rings or diaphragms; the cleaning solution softens and destroys these materials.

Also avoid soaking electrical parts, such as heated choke assemblies or solenoids. Some late-model Holley carburetors have Teflon-coated throttle shafts. Expose these shafts in cleaning solution only long enough to remove deposits. Extended exposure to strong solvents can degrade the Teflon coating.

You need a tank or bucket large enough to accommodate your parts basket. A 3- or 5-gallon bucket of carburetor cleaner allows the basket to be dunked directly into the container. Another option is to use a parts-cleaner tank, filled with a dedicated carburetor cleaning solvent. Don’t just “rinse” the parts in this solvent. Fully immerse the parts (in a steel parts basket) and allow them to soak.

When the parts have soaked long enough to remove all varnish and carbon deposits, rinse the parts in hot water and blow-dry with compressed air. My personal preference is to rinse in a mixture of hot water and Dawn dishwashing liquid, which does a great job of removing any residual solvents and oils. Follow that with a thorough hot-water rinse to remove the soap residue. Always blow all parts dry with compressed air.

When handling carburetor cleaner solvents, always wear protective rubber gloves and safety goggles to avoid skin and eye contact. Always keep the solvent away from any sparks or source of fire.

Media Blasting

Avoid media-blasting any carburetor part if at all possible. If it’s necessary to media blast your carb, take all precautions to protect the carburetor. Improper media blasting as a cleaning method for carburetor components is downright dangerous because it can damage surfaces as well as potentially contaminate the carb.

When you need to measure or verify various dimensions, such as baseplate thickness, linkage rod diameter, throttle bore diameter, etc., a quality dial caliper, micrometer, and small-bore gauges are necessary. If you plan to use drill bits to check, verify, or enlarge main jets, you must measure the drill bit shank with a micrometer to verify the actual diameter of the drill bit.

In some instances, with proper care, certain types of media may be used to clean stubborn deposits. Soda blasting is the safest because soda is relatively benign (not too abrasive) and is water soluble for cleanup afterward. Items such as base plates or empty carburetor bowls and main bodies may be cleaned with walnut shell or corncob media, as long as you don’t dwell the blast in concentrated areas.

Never sandblast any carburetor part; sand is far too abrasive. Aluminum oxide (in a glass bead cabinet, for example) may be used, but again, avoid concentrating the blast and be sure to use fairly low air pressure.

Avoid using any abrasive media for cleaning parts that have captive shafts because the media grit can contaminate the shafts and it can be difficult (or impossible) to flush out. Aggressive blasting can ruin precision orifices and mating surfaces and can prevent gaskets from sealing properly. Base assemblies and throttle shaft pivot points are easily contaminated; this can result in parts sticking and premature wear for shaft and shaft bore surfaces.

If you end up stripping fuel bowls and/or the main body down to a bare surface (by choice or by accident), the components may be re-plated with dichromate or zinc. A local plating shop can handle this, or the parts can be sent to Holley’s restoration shop. For that matter, Holley offers complete and extremely high-quality rebuilding/refinishing services if you prefer not to perform a rebuild on your own.

Measuring Tools

Although not mandatory for most carburetor service, a selection of precision measuring tools can be handy for measuring and comparing various components. These include instruments such as dial or digital calipers, micrometers, and small-bore gauges that can measure baseplate thickness, throttle bore diameters, and so on. If you plan to enlarge any jets or other orifices with a drill bit, you must measure the bit first with a micrometer to verify its diameter.

Written by Mike Mavrigian and Posted with Permission of CarTechBooks