Home Up QuadraJet 4



Notice the gasket hanging on the choke coil. If this gasket leaks, it will allow cool air in, instead of heated air. This will delay choke opening. Do not soak the choke cover and coil in carb cleaner. There is no reason to separate the coil from the cover.



The screw in the center of the choke housing can stay in place. It hold the linkage together. If the cleaning makes the linkage move freely, there is no reason to take it apart. If it won?t move freely, you may need to disassemble it and use some very fine sandpaper to polish the components. Don?t over do it or they will get sloppy and hang up anyway. Remove the top screw to remove the choke housing assembly.


Here is the choke housing removed from the carb. Notice several pieces of linkage. Some of these will come off without removing the screw inside the housing. Be sure you don?t lose them. You don?t need to take this all the way apart for cleaning if the pieces move freely. It anything sticks disassemble it.
The large heavy lug toward the front of the picture is for the fast idle. When this is raised up, the car is on fast idle. In the down position it uses the normal curb idle. It Must move freely, or the fast idle won?t operate correctly



This is the secondary lockout. In combination with the other choke linkages, it prevents the secondary throttle plates from opening when the engine is cold. Gravity move it one way, linkage pressure moves it back. Not the position. This is not easy to figure out with out a picture or good memory.

 



The ugly yellow link is actually a shiny piece of metal, when clean. It drops down in the slot where the end is hanging. This link is what attached to the center pin from the choke housing assembly, after it goes through the carb housing. This can be very difficult to align when assembling the housing to the carb. If you hold the carb on its side and let the link lay in the carb housing slot, it can sometimes help make it easier. The linkage rod at the top of the link goes to the choke place lever at the top of the assembled carb. The rod can be put in before or after the carb is assembled. The end just has a tapered cut and can be rotated into place. When the rod is attached at the top, it can?t rotate, and can?t come out.



There are two of these tamper resistant plugs on the front of the carb throttle body . They must be removed to reach the mixture adjustment screws. The mixture screws are extremely important when adjusting the carb. Your plugs may have already been removed. According to the EPA, the plugs should always be replaced after adjustments. I have never seen that happen and in fact is usually impossible due to the removal process.



One way of removing the plugs is use a hacksaw and cut a notch from this dot on the bottom of the plate, to the edge of the tamper plug. This cut will be at a 45 degree angle to the plate bottom. Make the same cut on the other side of the plug where you can see the other dot. Now use a chisel and knock out the metal next to the plug, and in-between your cuts. Use a punch and drive the plug out. This is really not as bad as it sounds. Yes it does leave a chunk of metal out of the bottom of the plate, but that?s okay.



The other method is to use the special tool designed to remove the plug. It?s a hold saw that cuts out around the plug. Notice the plug is deeper than the dots indicate. The picture below shows the removed plug.







Now you can see the mixture screw. This head style on the screw is called a ?Double-D? due to its shape. You can get it out with needle nose, but you need a socket or double-d tool to adjust it on the car.

 



Here is the mixture screw. The spring is a very important part. It keeps tension on the screw and keep it from turning on its own when driving. If the spring is too weak to do its job, just stretch it out a bit and it will work fine. Don?t stretch too much. The end of this screw is coated with carbon. It won?t operate correctly without cleaning.

With everything disassembled it?s time to clean the carb. You can do this with several cans of a good carb cleaner. It?s far more effective and easier to use a cleaning solvent made for carburetors. The regular parts tank won?t do the job. You can purchase a one gallon can of cleaner from your local parts house, but the Q-jet won?t fit in the can. Soak and clean the small parts using the basket supplied in the can. You can pour the solution into a plastic bucket, then soak the other parts.

DO NOT get the carb cleaner solution on your skin or any part of you! It WILL cause chemical burns that may need medical attention. It can blind or kill you. This stuff is wicked! Read and follow ALL warnings. When you remove the parts from the solution, rinse them thoroughly in running water. The water can be dried off or blown off with an air gun. Don?t leave them wet for a long time. Steel parts rust.




WOW what a difference the cleaner makes. We went from filth to almost new looking. If you use cans of spray cleaner you may get it functionally clean, but it won?t look this good. All the passages and internal parts MUST be this clean.
Match up the lower gasket from your rebuild kit. Install the throttle plate to the bottom of the carb body. Install and tighten the three screws.



Now you can actually see the components. The small Phillips screw seen in the lower front is the fast idle adjustment screw. There is a green shaft end toward the left with a roll pin stuck through it. The shaft is the secondary throttle shaft, and the pin in part of the cold lockout. This is what the lever hits to keep it from turning cold.



Now you can what the inside of the carb looks like clean. Every one of the holes and passages must be this clean. Every one of those holes either is for a screw, or is a functional passage. Make sure they are all open. You can use spray carb cleaner to blow through the passages and make sure they are all open. There is no need to rinse the spray cleaner away. Unlike the solvent in the can, it will dry out. While it?s not as bad as the stuff in the can, it is harmful and can hurt you through contact with skin, mouth, or breathing. It can cause eye damage. Use safety glasses and be careful.



Here are several small parts that come with the carb kit. Most of the gaskets are not shown. The clear bag on the left contains the new needle and seat, as well as seat gasket and needle spring.
The bag on the left contains the new choke coil retainers and screws that replace the rivets. There is also a gasket for the fuel filter, and choke housing seals. Be careful when you open these bags. Lose this stuff and you will be buying a new kit.

 



Pry the old choke shaft seal from the side of the carb body. It comes out very easily. Just remove the rubber, not the steel ring around it. Insert a new seal from the clear parts bag we just looked at in the last photo.



This is also in the clear bag. It is the vacuum passage seal. It seals the choke housing to the carb body. Without the seal, the choke won?t pull warm air, and the choke won?t open.



That yellow link is no longer yellow. Not it?s bright shiny metal. I?m holding the linkage rod to hold the link in place. The choke shaft goes through the link. Notice the link and choke shaft are both notched, so they must match position. This can be tricky to install, and may be done easier with the carb on its side. Make sure the linkages on the side of the choke housing don?t bind or get pinched when putting the housing in place. If it sound like a lot of watch at one time, it is. After doing it a few times, it?s fairly easy. The first time can make you say bad words. Be patient, go carefully, and don?t hurt the linkages. When all is in place install the single retaining screw in the choke housing.



The screwdriver tip in at the accelerator pump check ball hole. Drop the new check ball from the kit into the hole. Below the screw driver you can see the jet installed in the body/float bowl. The second jet is slightly to the right. The top of these jets are still discolored, but they are clean and the center of the jets are shiny clean. Don?t use anything abrasive to clean the jets. If you remove material, you make a larger jet.



You can see a bit of shine from the new check ball down in the hole. Install the retainer in the threaded hole. This one still needs a bit of cleaning. The rust is from 5 years of sitting. If there was water in your carb, it can happen in much less time. Don?t forget, sometime there is water in your fuel. The rust needs to come off, but it is not like the jets. As long as you don?t hurt the threads, a bit of minor abrasion won?t bother it at all. The bottom of the retaining screw head must also be in good shape so it will seal.



Just a reminder. This is the adjustment for the primary metering rod lean stop travel. If you turn this down, the carb will be leaner at light throttle and idle. Raising it will make it richer at light throttle and idle. Most of the time just leave it where it is. Unless you have a gas analyzer to make adjustments you will have a hard time getting this right. Remember we never took this out, or turned it. There are no fuel passages under it that need cleaned. Soaking will removing everything necessary. In this close shot you can see some of the brass passage metering inserts. Don?t try to remove them. Just make sure they are clean, and the passages open.



A bit blurry. These are the new needle, seat and seat gasket.



Install the seat and gasket. Be sure to use a screwdriver that fits the two notches. Just turning with one notch will damage the soft brass. Make the seat good and snug, but don?t get carried away. You don?t want to damage it. You also don?t want engine vibration making it come loose.

 

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