*Note this kit is the K551-S, all the steps are the same, and there is only an extra step at the end to reconnect the stock air cleaner. If you are using the square cleaner that comes with the K551, then stop following these instructions when the stock cleaner adapter is installed and bolt on the one in your kit.
I purchased this kit from Carbs Unlimited and it did not come with very good instructions. So I combined instructions I found on the web and the poor ones that came in the kit. I decided to write up how I completed the install and include pictures so that I could try to help some people out when they install their Weber.
1990 YJ, Colorado Red with Laredo markings
The engine is a 1999 re-built 4.2L with the stock Carter (this is where I would rip on the Carter but thatís been done)
To replace the stock Carter with a Weber 32/36 Progressive carb yet still keep the stock air cleaner.
It took me 4.5 hours in sub zero weather; it would be a good idea to devote an afternoon for the swap and to tune it. This is not something you want to rush, you are messing wih your fuel delivery system and it very important that itís all set up correctly.
-In the box-
1x Weber 32/36 DGEV Carburetor
1x Carburetor Adapter (Two pieces)
1x Hardware Kit
1x Linkage kit
1x Chrome Air Filter / Stock Air Cleaner Adapter*
*K551 / K551-S
Different Diameter pieces of Vacuum hose
1x 2í length of Fuel Line
Standard and Metric box/open end wrenches
Socket set (also Standard and Metric)
6mm Allen Wrench (I did not have one so by luck a Torx 30 bit will work if you donít have the Allen wrench)
Gasket Scarper / Knife
Tube of Loctite
Gasket Sealer (You must use a sealer that is NOT RTV or Silicone)
New Fuel Filter
Adjustable Fuel Pressure Regulator (I got a Mr. Gasket one from Advance Auto $30)
Extra Vacuum Hose
New Hose Clamps
Y or T Connectors for Vacuum Hoses
New Return Spring for Throttle Linkage
1. Remove the stock air cleaner if you are using the square one or slide the stock one to the side if you are reusing it.
2. This is a big one. LABEL EVERYTHING. When you unhook something from the Carter, label both ends with a piece of tape and a number or letter written on each. This way you know what went were and incase you need to hook something back up.
3. Place a rag under the fuel filter to catch spilt gas and remove the filter. It would be a good idea to have the engine cool so it lessens the risk of fire. Unhook the filterís three lines and toss the spent filter.
4. Disconnect lines form the Carter one at a time, and remember to label them!
5. Disconnect the electrical hookups to the Carter, Make note of the small one wire blade connection on the electric choke; you will need it for later
6. Once all the lines are removed, disconnect the throttle linkage where it connects at the bracket on the manifold (the kit comes with a new linkage so keep the old one on the Carter)
7. Break loose the carb mounting nuts and lift the Carter free from the intake manifold.
8. Stuff a clean rag in the intake opening to keep it clear of junk falling in.
9. If the carb mounting studs did not come out with the nuts then they are jammed in the intake. You can spray them with something to loosen them up; just donít let it get into the intake manifold. I used a small pipe wrench to remove the two that were stuck, as you can see in the picture below after I removed the Carter.
10. Now clean the mating surface of the intake manifold. (Before I removed the Carter, I noticed that it was very loose, almost and inch of play left and right. After removing the carb I found there was not gasket between the Carter and the manifold, it was clean as a whistle, but I still scraped it clean just to be sure.)
1. The adapter plate is a two piece set with 3 gaskets that assemble in order, each plate and gasket is different and needs to go in the correct order to line up. Below is a picture of the top view for each piece and in what order they are to be assembled. You need to build them up on the intake one at a time, you canít do it all at once and then drop it into place.
2. Take the gasket on the left (Two large holes, four little ones) and coat it with gasket sealer and set it on the intake manifold. Then set the bottom adapter plate (the one without the hole/plug in the side of it) on the gasket. Use the four chamfered bolts (have a flat top and will fit flush into the plate) to hold down the plate, donít forget to use the Loctite. Torque to 12ft/lbs.
3. Next coat the intermediate gasket (middle one, two large holes, eight small ones) with sealer and place on bottom adapter plate. Then install the top adapter plate onto the intermediate gasket. Note that the vacuum hole should be facing toward the front of the Jeep. The picture shows that the plug is installed. You should have the power brake booster fitting installed, not the plug, it will be used later when you hook the vacuum lines back up. Then use the four cap screws (small screw with a cylindrical head) and a little Loctite to hold it all down. Torque to 6ft/lbs.
4. Now take the carburetor gasket (should be the only one left, large hole in the middle) and apply sealer, then place on top adapter plate. Next install the carb mounting studs (looks like a bolt without a head) again with a little Loctite. Theses bolts should be hand-tightened into the adapter plate.
5. Time to crown the intake manifold with your new Weber. Set the Weber onto the adapter plate with the linkage facing towards the rear.
6. Install the throttle cable bracket onto the two studs closer to the left fender. Then install the washers and nuts provided onto the four studs to hold the Weber in place.
7. Cycle the linkage to insure there is no binding or sticking of the linkage. Now is when to adjust it to prevent problems later. When itís all moving smooth, tighten the nuts to 12ft/lbs.
8. Connect the bottom of the snap-on-rod to the bell crank. It snaps into the same spot the old one was. You cannot use the same bracket for the spring to return the throttle linkage so you will have to adapt a new one. I made one out of a thin ribbon of metal with holes in it. I bolted it to the other side of the EGR valve and reused one of my old springs.
9. Now its time to start hooking up vacuum lines and other connections. Remember that little electrical connector? Well it slips into the same place on the new Weber, just slide it on. As for the vacuum lines, I have included two pictures below. Top is the connections on the carb and what they are. The bottom one was given to me by Tshark299 and does a great job showing what needs to be hooked up and where it goes. Some hoses you will need to cut and make a new connection, others can be removed completely and the other end of the connection plugged. This is what took me the longest time, donít rush and just take it slow. And remember the brake booster connection on the plate? Thatís what goes to the manifold vacuum on the second picture.
10. Next install the fuel regulator, fuel line and fuel filter. Install the fuel filter in place of the old one. Then install the fuel regulator after the filter, it should come with instructions, but itís not that hard to figure out. There is an in and an out side, run the fuel hose form the filter to the in and the out to the carb fitting for the fuel (see carb diagram above). The instructions that came with my Weber said to set the regulator at 3psi. Make sure all connections are secure and you used hose clamps to avoid fuel leaks. Here is what my regulator looked like after install.
11. This is where the K551 and K551-S kits separate. If you have the K551 that uses the new square filter install it according to the instructions that came with your kit, itís not hard to figure out, just bolt on the air filter. If you are installing the K551-S place the gasket onto the intake of the Weber. Then bolt down the air cleaner adapter onto the top of the Weber and install the short stud into the adapter. Now the new height of the intake is about 1.5 inches higher than the Cater, so you need to adjust the air cleaner base to compensate. I removed the stock stud to hold everything down and installed the new longer stud and used new nuts and washers to hold it to the bracket on the valve cover. Then on the stud I placed a large nut, about on inch high, and then the large plastic washer. Then set the air cleaner back on and set the top of the cleaner on. Donít crank it down, just look at how it lines up and add more washers under it if you need it higher. After you get it just right, tighten the wing nuts on the cleaner and the Weber. It is important to be sure the hood will close with the new height of the air cleaner, it so be fine, but just to be sure. Hereís how my Weber looks after the install and the adapter plate attached.
12. Now itís time to fire up the engine. It will turn over several times before the motor fires (if you hooked everything up correctly that is). Leave the engine running and look for fuel leaks. Once the engine reaches operating temperature itís time to adjust the mixture and idle speed screws.
The Idle and Mixture Settings:
I used the instructions found at http://www.redlineweber.com/html/Tec...lean_best_.htm
I feel I donít need to copy the instructions to here, so read them there.
I am very happy with the results of the swap. My Wrangler runs better in every possible way over the Carter. The next step for me will be to do a ĎNutterí bypass to take the computer totally out of the loop. I have done the best I can to explain how I installed my Weber carb. My only plan was to help other like me, who got poor instructions and really did not have a clue on what to do.
I would like to thank tookie, Tshark299, Richmond 88 YJ, King03Kev, biblicone, mrmustang, t rexx70, mean90yj, tcourdin, and everyone on JF for putting up with my questions and for all the help. I hope I can return the favor one day.
Enjoy your new Weber and I hope to see you on the trails!