Now the right (driver's side) one works, but the not the left. The throttle allows you to control how much air flows through the carb. carter carb> running rich - Jeepz.com The idle mixture screws work pretty much for idle only. I did adjust the mixture screws using the vacume gage. Turning the screws clockwise seats the screws and leans the idle mixture. The screws at the base of the carb are for idle only, if they are between 2-3 turns out, don't touch em. Adjust the metering rods. Give the engine a second to catch up. First run the screws in all the way until they seat, lightly. This can be caused by several different things, but the most common is a too-rich or too-lean fuel mixture. I'm having a problem finding the best lean also. Turning them in leans out the idle mixture. When the rpm starts to drop, turn the screw back 1/4 turn and leave it . Mixture idle Screws Pre-Set: Fuel Economy, Fuel Economy, Fuel Economy, That is Why We Pre-Set this Adjustment. As the throttle valves are opened, more of the Plan of Action - Carter BBD CARBURETOR REBUILD TIPS DO'S DON'TS Where Fuel Meets Air Cadillac 472 Fuel System Part 6 - Idle Mixture Adjustment Using Vacuum Gauge Idle Mixture Adjustment on 4 Barrel and 2 Barrel Carburetors Tecumseh Carburetor Repair - Vintage Factory Training Otherwise, you will experience vacuum leaks and not be able to accurately adjust the mixture. $19.95. Use the curb idle speed adjusting screw (the one that doesn't seat on the fast-idle cam) to set the idle speed to between 600 and 750 rpm. Given that your Jeep has the Carter BBD, with stepper motor adjusted jets, and the associated very complex and failure-prone emissions control systems, my bet is that the fault lies there and not with the idle mixture adjustment. As soon as you step on the gas the main jets take over the job. Willys jeep Carter WO Carburetor EP1 How to adjust carburetor idle mixture screws *UPDATED* Fine Engine Tuning With A Vacuum Gauge Jeep CJ - YJ Carburetor Issues - Diagnosis and Plan of Action - Carter BBD How to rebuild an Did you find this helpful. Shaft = 1.4975". So, if a sensor goes bad and feeds a constant signal to the carb, you get problems. There is a stepper motor that keeps changing the rpm, and fuel mixture. You might have to remove plugs that cover the idle adjust screws, but after that it is not a big deal. Like I said, I can email you a copy of this manual. The Willys jeep Carter WO Carburetor EP1 How to adjust carburetor idle mixture screws *UPDATED* Fine Engine Tuning With A Vacuum Gauge Jeep CJ - YJ Carburetor Issues - Diagnosis and Plan of Action - Carter BBD They simply control the amount of fuel and air mixture that is delivered at idle. To adjust the light cruise air/fuel . 15The 2 barrel Carter 8383S, 8384S carburetor BBD fits Jeep, Wrangler, Eagle CJ7 - 1982-1991 Jeep 6 Cyl 258 CID. Before I removed the electronic choke housing, I made the mistake of not marking its original position. As with all carburetors, the BBD requires periodic adjustments. The dimension refers to the front to back dimension of the flange mounting holes. It is a 1-7/16" throttle bore carb. Historically, those BBD's tend to NOT idle at all. The idle mixture screws determine the amount of air and fuel. Unscrew them counterclockwise 1-1/2 turns for the initial adjustment. These are viton tipped and ethanol ready. Then I just removed the idle mixture screws to adjust for idle quality. 4WD. It did help reduce the sputter, but it didn't solve it. Jump to Latest Follow NEWS PARTS JEEP & 4x4 ATV & UTV . Carter BBD adjustment? Carter Thermo-Quad carburetors (Note: Long threaded idle mixture screws will need to use 2 sets of spring #2021 to work properly) Carter WCFB carburetors. Locate the idle mixture screws at the base of the carburetor. Adjust the accelerator pump linkage. It almost sounds as if only half of the cylinders are running. Carter BBD, 2-barrel carburetor, needle and seat assemblies. The dimension (C) between the upper edge of choke valve and air horn wall should be as listed in specifications. CLIMATIC~ CONTROL CARBURETER. adjustments should be made with the engine at full operating temperature. MANUAL. Before, both idle mixture screws did nothing when turned all the way in or out. The manual says that has to be adjusted during flow testing so you shouldn't mess with the factory setting. Then I just removed the idle mixture screws to adjust for idle quality. The idle is very rough and doesn't rev very well, or loud for that matter. Inspiration for this arrangement was provided by the federal government through its exhaust emissions regulations. The idle mixture screws work pretty much for idle only. turn the idle adjustment screw about 1.5 full turns, then lower the idle while its running. Carter BBS carburetors. First run the screws in all the way until they seat, lightly. b) Idle mixture screws . If the idle is good, the idle screws are not your problem. Make sure you adjust the idle speed after every adjustment (you can tell 800 rpm or so by ear.) The feedback system used on the 1985-1986 models consists of a duty cycle solenoid that "trims" the idle and main air bleeds, there is a throttle position sensor and a stepper motor for idle speed control, this also incorporates an idle position switch. Unscrew them counterclockwise 1-1/2 turns for the initial adjustment. You mention a Carter BBD carb, but go on to mention about "toe in the throttle and open the secondaries". You will tune each side if the idle circuit for maximum vacuum, then adjust the idle speed with the idle stop . Spray starting fluid around the base of the carburetor and intake manifold. Overall length = 1.675". 1977-1980 Willys Jeep Carter . Adjust idle mixture by turning idle mixture screw slowly clockwise until the engine runs poorly. The BBD was a two-barrel carburetor manufactured by Carter during the 1960s and 1970s. To adjust, bend tang (C). . Apply a light closing pressure on choke lever (B) to move the choke valve toward the closed position. Too hard and you will damage the screw. 42 carter 2 barrel carburetor diagram. A vacuum gauge attached to one of the vacuum ports on the base of the carb is needed for setting proper idle mixture. Locate the idle mixture screws at the base of the carburetor. It seems to be when both of the idle adjustment screws are all the way in! Start the engine. At idle and turn one of the idle screws clockwise until the engine begins to stumble, then ccw for 1/2 turn. Do the same on the other idle screw. Idle Problems. 8. Rough, unsteady idle problems are all too common with the Carter BBD on the 258 CID engine. Rough, unsteady idle problems are all too common with the Carter BBD on the 258 CID engine. Now that the carb is installed the engine runs . The BBD was produced exclusively for Chrysler, Plymouth and Dodge vehicles. This carb uses moving metering enrichment rods, with a calibrated spring. Okay, I am looking at an exploded diagram of a '77 Carter BBD right here. The idle mixture control screws (2 of them) should each be out approximately 1 to 1 1/4 turns from lightly seated. Both holes for each barrel, thread-wise, are only around 1/4th of an . Could that be true? The mixture screws only affect idle mixture. To do it you need to have the timing set right first. none of this timing by ear stuff because it tends to make timing too advanced. You also need a good set of plugs. Fouled plugs won't be as responsive to mixture changes. Then lower the Idle as slow as you can without it being rough. . Fast idle cam rod carter bbd item 2 on diagram c2 bbd 8 995 choke pull off rod carter bbd afb item 8 on diagram c2 bbd 6 1595 acc pump rod carter bbd. Note the wire bundle exiting the Stepper Motor (back of carburetor) and myriad vacuum hoses. . Adjusting the Idle Mixture Screws The idle mixture screws only affects idle. On this 258/4.2L engine, despite the busy appearance of the installation, the idle mixture screws are accessible with the air cleaner assembly in place. It's hairsplitting but worth noting that adjusting the idle mixture screws doesn't affect the air/fuel mixture itself, but simply the volume of air/fuel mixture admitted to the idle ports; only the idle jets and bleeds affect the actual mixture ratio admitted to both the idle port and transfer slots. Adjustment of the idle circuit is fairly easy. The idle mixture screws determine the amount of air and fuel distributed by the carburetor. As with all carburetors, the BBD requires periodic adjustments. Another way: Bring the engine to operation temperature. Carter YF carburetors. How do you adjust Carter BBD? Do this two or three time, each time adjusting both screws (if it's a two barrel). The Carter BBD has an idling circuit that is always seeking. When the mixture screws are all the way in it reads 20 and has . Pull the factory 2 Barrel BBD carter, let it sit in cleaner for about 2 hours and blow it out with compressed air. In the same year, the 318's BBD gained a mixture adjustment for higher altitudes, which could be set from the top of the carburetor; this was only used on cars sold in high-altitude areas, and was replaced in 1982 by a separate mechanism. By-pass, economizer, idle port, idle adjustment screw port, and bore of throttle body flange must be clean . The pickup tubes are very small and get plugged with debris and the idle circuit quits. IF the PCV line is plugged, the hot idle will be very slow as the PCV acts as an air bleed. 4.2L. Carter W1 carburetors. …. WCD, WGD, WGD-1 Idle Mixture Scr Idle Adjusting Screw Spring Idle Mixture Screw- 10-32 x 1.206" OEM # 30A-58 Idle Mixture Screw- Carter WCD, WGD OEM # 30A-41 I am trying to tune the idle on the carburetor, but the highest vacuum I get is with the mixture screws all the way in (lightly seated). Carter BBD Idle Circuit Idle Mixture Adjustment Bring the engine to operating temperature. I have a new carburetor that is a remake of the carter bbd on my vehicle. Adjust the dashpot. Hook up a vacuum gauge to a port that has steady vacuum. Turn both idle mixture screws out 1/2 turn. The BBD was produced exclusively for Chrysler, Plymouth and Dodge vehicles. When We Pre-Set this Adjustment on Carburetor We Make Sure the Choke is Opening the Choke Valve Normally and Make all the Necessary Adjustments on Our Live Engine to leave the Carburetor Ready to Go. 6 CYL. Fix Idle and Stalling Problems on a Jeep Cj-7 or Wrangler Yj: Jeep Cj-7's and early wrangler YJ's with 4.2 liter engines came with a rather lowsy carter bbd carburetor which of goes out fo adjustment. Picture 1: Check for fuel on the carb. Use a socket or nut driver to take away the 2 bolts that maintain the carburetor to the engine. The Idle System provides a mixture for idle and low speed performance; the Accelerator Pump System provides additional fuel during acceleration; the Main Metering System provides an economical mixture for normal cruising conditions. As soon as you step on the gas the main jets take over the job. The BBD was produced exclusively for Chrysler, Plymouth and Dodge vehicles. For richer mixture, turn this screw out; for leaner mixture, turn this screw in. . Carter AVS carburetors. Start the engine and warm it up. It basically never stabilizes, and it keeps adjusting based on the feedback loop from half a dozen or so sensors. . I decided to make a newer video that hopefully explains WHY you adjust carb idle mixture as well as shows how. Idle Adjustment - Like most other carburetors there are two screws on the front base to adjust the mixture. All of our complete rebuild kits include needle and seat assemblies. https://www.carburetor-parts.com is providing this video which illustrates the choke circuit on a Carter 2 barrel carburetor. The Carter Model BBD dual venturi carburettor utilizes three basic fuel metering systems. This can be caused by several different things, but the most common is a too-rich or too-lean fuel mixture. Here is the Carter BBD operation and repair manual (pdf) . Alternating between the screw turn in 1/4 turn at a time. The screw closest to the carb body is the COLD idle adjustment; the one outboard of closest to the bottom of the frame is the hot idle adjustment. This original equipment (OEM Carburetor) with stepper motor is recommended for states with emissions testing. It will idle fast when you first start it up until it gets warmed up, this is called high idle. and then you're ready to work with the idle speed and mixture adjusting screws. We cover many parts for the Carter BBD and other carburetor s. . and idle adjustment screw port. Carb Idle Mixture Screw - How To Adjust Properly (EXPLAINED/DEMONSTRATED) How to clean up edelbrock carburetor How Carburetor Works adjust and set idle mixture screws Jeff Smith's Garage Edelbrock A Carburetor is a mechanical device for mixing air and fuel. They simply control the amount of fuel and air mixture that is delivered at idle. Idle Mixture Screw - Carter WCFB (Pair) 10-32 x 1.2 40-4 $ 7.25 Hot Air Choke Cover Cap (Plastic) 2 1/8 x 1/2 - can use spring 66-32 - No name on cover . It's easier for me to tune than everybody else because I just put it on the dyno and adjusted the idle and cruise fueling on there using a 5-gas analyzer. Connect the end of a vacuum gauge to the vacuum nipple on the carburetor. Rebuilding Carter BBD Carburetor Part 1 Edelbrock Carb Tuning Springs and Squirters Avoid this Edelbrock Carburetor Tuning Mistake !!!! Fast Idle Cam Rod Carter BBD item 2 on diagram C2-BBD-8 $ 9.95 Choke Pull off Rod Carter BBD / AFB item 8 on diagram C2-BBD-6 $ 15.95 Acc Pump Rod Carter BBD . The idle mixture screws only affects idle. 124, 3/4 to 1 3/4 turns for normal opening on the CJ-5. The faster air flows through the barrel, the more fuel it draws into the airstream. Step 2: Take away the carburetor. The idle adjustment screws are shown in the last pix. 83 I-6, 5 speed. A Carter BBD for a '70s vintage 318 engine is a 1-1/4" 2 Bbl carb. Location: North Carolina. This is the official Mopar Parts listing and diagrams for the 8383 and 8384 Carter BBD two-barrel carburetor used on Jeep CJ models in the 1981-86 era (also similar to the '87-'90 Jeep YJ Wrangler 4.2L BBD . Click to see full answer Carter BBD service manual, 1982. You can get a clue to which it might be by removing the lid of the air cleaner and looking down at the metering pins. But it idles great. 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