Winged Warriors/National B-Body Owners Association
SixPack Carburetor Rebuilding

Text and Photos by Sue George


The Holley 2300 series carburetor, which is used on the Dodge and Plymouth 3x2 bbl set-ups, is very easy to rebuild. The photo at left compares the inboard carburetor (left) to the outboard carburetor (right).

The inboard carburetor houses the choke assembly and choke pull-off, accelerator pump, idle mixture screws, power valve, primary jets and the fuel bowl vent.

The outboard carburetors are either all the way on or all the way off during operation. They snap open at about 3200 RPM with the stock springs installed on the vacuum-operated diaphragm assemblies.

I'll start this disassembly and rebuild using the inboard carburetor, as the outboard is a very similar stripped-down model, which I'll cover at the end of this article.

First mount your carburetor on 5/16" bolts to prevent damage to the throttle plates during disassembly. While the carburetor body is still assembled so you can gain some leverage, break the fuel inlet fitting, fuel bowl sight plug and the float needle and seat screws loose.

Next remove the fuel bowl vent valve assembly. There are two different styles used on the 2300's. The one shown at right is the newer non-replaceable metal and spring type, which has two screws holding it to the top of the fuel bowl and a rod bracket screw. Before taking the rod/spring assembly apart, notice how the spring is mounted so as to properly open and close the valve.


The older non-emission style used a simple rubber vent valve hung from the rod. Your carburetor kit will include a replacement rubber vent valve. However, if your carburetor has the newer style vent valve, clean it carefully in solvent and set aside for later re-installation.


The photo at left is an internal view of a complete inboard carburetor fuel bowl.

Finish turning out the fuel inlet fitting and the fuel bowl sight plug. The sight plug is the screw on the side of the fuel bowl, so named because on a Holley you remove this screw to check the fuel level in the bowl during operation, by which you can then adjust the float level with the externally mounted float needle screw on top of the fuel bowl (a real nifty convenience of a Holley!).

By now you will have noticed that everything you've removed so far has either a gasket or a seal on it. If you are not familiar with all of these, I highly recommend trying to keep them intact and taped to a piece of paper for later reference. The rebuild kits are common to all 2300 series carburetors for many years and different styles, so they include a lot of similar but incorrect gaskets and seals and many you will not end up using in each kit.

You are now ready to remove the fuel bowl screws (the screw gaskets may be stuck in the indentations in the bowl) and pry the fuel bowl away from the carburetor body. Pull the fuel bowl gasket away from the bowl and body.

Now turn the fuel bowl over and remove the four Phillips screws holding the accelerator pump on, and gently pull the whole assembly down away from the fuel bowl. It will consist of the cover and pump arm assembly, a rubber diaphragm and a spring (shown in photo at right). There will be a new rubber diaphragm in your kit. You have now exposed the hanging ball fuel inlet. This assembly is staked onto the fuel bowl; do not disassemble this! See the carburetor adjustment pages included in your kit for proper clearance measurement of the ball. Otherwise, simply make sure the ball is clean and moves freely when you soak the fuel bowl.


Going back to the top of the fuel bowl, since you already broke the screw loose earlier, you can now remove the float needle valve and seat assembly by turning the nut out. A new needle valve and seat assembly and a gasket will be supplied in your kit.

Next, remove the two screws on the float tang and lift the float assembly out of the fuel bowl. The fuel bowl is now bare and ready to soak.

Note: inboard carburetors use brass floats while the outboards use black fiber composition floats. Contrary to what most motorheads believe, Colt Industries (Holley) technicians claim that their fiber composition floats are made to withstand all exotic fuels without damage. Either way, if you are rebuilding a carburetor that you have not ever previously run, I'd recommend replacing the outboard floats now. They are not included in your kit, but are available through a good auto parts house.


The photo at left shows the float needle valve assembly parts above the fuel bowl and the brass float assembly at the bottom.

Once the fuel bowl assembly is separated from the main carburetor body, the primary metering block is exposed. The inboard carburetor metering block houses the idle mixture screws, main jets and a power valve.

The photo at right shows the side of the metering block that faces the fuel bowl. This gasket is common to the two surfaces, also serving as the fuel bowl gasket. A new one is supplied in your kit.

Start disassembly of the metering block by removing the two main jets with a wide blade screwdriver. Use care with the jets as they are soft brass and very easily damaged.


Next remove the two idle mixtures screws from either side of the metering block, making sure the cork gaskets come out of the seats. New cork gaskets will be included in your kit. Thoroughly clean all of these parts and blow out the jets with compressed air before reinstalling.

Most inboard 2300's use a metal bowl vent splash shield which is a small metal bracket that slips over the two pins at the top center of the fuel bowl side of the metering block. Unfortunately, the carburetor I used for this article did not have this splash shield intact. The purpose of the splash shield is to provide foaming control of the fuel under hot operating conditions. This is not a part that is supplied in the kit. If your carburetor is so equipped, soak the shield clean and re-install it directly against the metering block and then install the new metering block-to-fuel bowl gasket over the top of it.


The photo at left shows the opposite side of the metering block, the side that faces the carburetor body. The only removable part here is the power valve which turns out with a 1" wrench or socket. There is a gasket under the power valve and a metering block-to-main body gasket. Once the bare metering block is soaked and clean, blow out all passages with compressed air. A new power valve and gaskets will be supplied in your kit.

See the carburetor adjustment specifications and instructions included with your kit for proper selection of a gasket to match the new power valve that is provided. Reinstall the jets snug, but do not overtighten! Torque the power valve to 100 inch lbs. Turn the idle mixture screws in gently until you feel them bottom out and then back them out 1-1/2 turns. This will get the engine running and then you will need to make further adjustments to fine tune.

A little tip .... it is easier to get the cork gaskets seated in the needle valve seats if you first turn them onto the needle valves.

Now you're ready to move on to the main carburetor body (the throttle body). Shown at right is the complete assembly minus the fuel bowl. Start disassembly by removing the choke pull-off assembly on the side.


There are two mounting screws to remove and then you can maneuver the pull-off rod out of its slot as shown at left. Do not soak this assembly, as it contains a rubber diaphragm that will be damaged by the solvent.

You can now turn the carburetor body on its side and remove the eight Phillips screws from the bottom side of the throttle plate. There is no need to further disassemble the throttle plate and it is now ready to soak. A new throttle plate-to-body gasket is supplied in your kit.


Looking down into the top of the throttle body, you can see the pump discharge nozzle in the center, as shown at left. Disassemble it by removing the Phillips screw and pick up the nozzle and gasket. Then turn the body upside down and catch the discharge needle (or discharge ball, depending on the year of the carburetor) as it falls out. Clean all of this thoroughly and reinstall using the new gasket supplied in your kit.

The newer emission-style inboard carburetors have a bimetal strip mounted in the center of the rear side of the throttle body. This was a pressure relief system that Holley experimented with in the early 1970's. Its purpose was to release pressure in the event of a backfire so as to preserve the power valve. It was not always successful, as we are all familiar with that little mishap causing complete power valve failure! This pressure relief system is not replaceable, but it can easily be disassembled, as shown, cleaned and re-installed.


This concludes the disassembly and cleaning of the inboard 2300 carburetor. Assemble in reverse order using these same instructions. Always refer to the literature included with your kit for carburetor adjustment procedures.

Most good kits include a cardboard instrument for gauging your fuel float adjustment. Once the car is running, you can fine-tune your float setting, using the sight plug and needle valve adjustment on the carburetor.



The photo at left shows a completely assembled outboard 2300 carburetor. It does NOT have idle mixture screws, an accelerator pump, jets, power valve or a choke assembly, so it is a very simple carburetor.

The vacuum pod mounted on the side of the carburetor body and the threaded linkage rods between the two outboard carburetors and vacuum provided via a port in the pod flange are the only means of controlling operation of the two outboard carburetors.

Do not allow the vacuum pod to come into contact with solvent. Remove it from the carburetor body before soaking the body (vacuum pod removal and disassembly is covered at the end of this article)!

Next remove the outboard's fuel bowl. Disassemble the float assembly and soak the bare fuel bowl. There is no need to soak the fiber composition float in solvent.

Once the fuel bowl has been removed, you will have access to the metering plate assembly. The six screws holding on this series of metering plates will have to be removed with a clutch head screwdriver (available at most auto parts stores) to avoid damaging them.

Once the clutch head screws are removed, you can pry apart the very simple sandwich of two metering plates and two gaskets. The photo at right shows the metering plate assembly disassembled.

It is very important to use the correct gaskets here, as your kit will include several look-alikes that are not correct and if used will severely affect carburetor performance. Clean the plates and reassemble with new gaskets. Only snug the clutch head screws, do not overtighten.


Helpful hint: The small Holleys often have a problem with the fuel boiling during high temperature operation of the engine, which can deplete the fuel in the lines all the way back to the fuel tank. A lot of stress to the Chrysler starter results during cranking time to refill the fuel lines, filter and carburetor float bowls before start-up can occur. An electric fuel pump will virtually eliminate this problem.

Another remedy that helps the fuel boiling problem significantly and is not as obvious as the electric pump is to replace the original paper-thin carburetor base-to-intake manifold gaskets with 5/8" Ford #CG-539-A fiber gaskets. These will raise the carburetors a bit from the heat source and also insulate them. Make sure your air cleaner has hood clearance before adding the thicker gaskets.


To remove the vacuum diaphragm housing, first pry the C-clip off the diaphragm rod. Mark the position of the rod's adjustment by wrapping masking tape around the threads before removing the rod assembly from the carburetors. This will save a lot of time during fine tuning later.

Break loose the four mounting screws and then remove each one, noting that the two longest screws go through the two thickest flanges and the two shorter screws go through the thinner flanges.

On the mounting flange that has three holes, the center hole is the vacuum port and has a cork gasket that seals it against the carburetor body. This cork gasket must be replaced for a proper seal. Make sure the vacuum port is clean.

The next steps are not necessary unless you need to replace the vacuum diaphragm inside of the pod. You can check it by holding the vacuum port next to a sensitive area of skin and pushing on the vacuum diaphragm lever. You should feel the air movement. If not, the diaphragm is defective.

Next disassemble the housing by removing the six Phillips screws from the outer edge. Visually inspect the diaphragm for cracks and tears, particularly around the metal center. To replace the diaphragm, first set the spring against the front cover housing. Lay the new diaphragm over it and put the back cover over the diaphragm.

While depressing the diaphragm lever, replace the six housing screws, tightening a little at a time while working around the outside edge of the housing several times. Note: the pod flanges easily break if even pressure is not applied all the way around while tightening the screws.

When remounting the pod onto the side of the carburetor, slip the diaphragm lever over the adjustment rod and force the C-clip back into the groove. Then start each screw through the housing and carburetor body and snug each one a little at a time. Do not overtighten or put the casting in a bind, as these flanges also break easily. You will also have to take particular notice that the vacuum port cork gasket does not obstruct the hole before tightening the housing onto the carburetor body.

If the adjustment rods have been turned in or out during the rebuild, you can now return them to their original position as marked by the masking tape. During engine idle and operation below 3200 RPM, the outboard carburetors must be closed off or they will drastically affect the engine idle and low end performance. To check that the rod is adjusted so the carburetors are closed, simply try to push the throttle plates closed with the rod once the car is running. If the engine idle smoothes out with the rod pushed back, it needs to be turned out a little more. Continue with this procedure until you are sure the outboards are completely off.


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