After rebuilding, the 2 Jet idled smoothly. Then, it began to miss at idle, and stall under load in gear. Runs alright when throttle is advanced. Driver side idle mixture screw changes idle, but p***enger side idle mixture screw has no effect at all. When aiming thermo gun at exhaust, #1, 7, 6, and 4 run fairly hot - 600*. #3, 5, 8, and 2 run colder at idle - 180* or so. I note that the inner cylinders on the left side run colder and outer cylinders on the right side also! Could the ineffective adjustment on the p***enger side idle mixture screw relate to those cylinders? Things I've done so far: Changed cap and rotor for new (HEI), changed all plug wires for new. Swapped plugs between colder and hotter cylinders (new plugs), then swapped plugs back. Checked plug spark with plugs removed - all fire. Checked valve adjustment. Took throttle body off carb and flushed out idle mixture p***ages with carb cleaner. Pulled out one handful of hair! I welcome your thoughts, including a suitable replacement for this old carb. It's on a bracket T-Bucket stock 283 that my girlfriend races for loads of fun.
Your idle circut is pluged up =dirt ,thats why the screw doesn't have any effect.Also look at the end of the idle mix svrew ,may have broken the tip of it off in the carb body.Has been known to happen.
either idle circuit plugged on the side that won't adjust, or moderate sized vacuum leak on the carb, carb base, or anything on the intake manifold related to those runners that feed off that side. Fix, don't buy a new one. You'd buy new if there was a major visable problem like heavy corrosion in the fuel bowl, or cracked casting etc. The rest can be fixed
Both screws are sharp. But, I'll swap them to see what happens. Blew out the idle circuit in the throttle body with carb cleaner. Shot cleaner through like a champ, including into the barrels. (big and small holes) ****erfly's shaft is loose, and could cause vacuum leak. What to do about that?
One side of the idle circuit is plugged. You had it clean, as it worked well originally, but foreign material, either from disturbing the fuel line or from the tank as settled in the idle circuit. OR You have a large vacuum leak on one side, possibly one of the carburetor mounting bolts has worked loose. If it were the throttle shaft, you would still be able to adjust it out by opening the mixture screw on that side. Suggestions: (1) Recheck snugness on all carburetor mounting bolts. If that does not solve the problem, then: (2) Remove carb, dis***emble and blow compressed air in both directions through the complete idle circuit, including the idle jets in the venture cluster. AND (3) Install a good inline fuel filter between the fuel line and the carburetor. And just in the FWIW category, if it were the throttle shaft, it would be the driver's side with problems (unless you are posting from England, or some other area where they drive on the opposite side of the road). Jon.
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