Rough running fuel and carburetor related

Welcome to 2CarPros.

Since the fuel lines were worked on, my first suspect is that the fuel filter has plugged and restricting fuel to the engine. Thus, it starts, then slowly runs out of fuel and stalls the engine. Or, the pump is going bad. Have either of those been checked or replaced?

I need to know if this is a 4bbl or 2bbl carb. When it stalls, does it start right back up?

Here are the mixture adjustment procedure for the carb since it is new. I thought it may help. The two attached pictures are the specs for adjustment.

MIXTURE ADJUSTMENT PROCEDURE
Two methods of idle mixture adjustment are recommended. The "CO Meter Procedure" may be used on all except 6 cylinder engines if a suitable CO meter is available. The "Lean Drop Procedure" may be used on all models.

Air cleaner must be left in place and A/C control, if equipped, must be in off position during adjustments. Disconnect and plug vacuum hose at vacuum advance unit (all) and vacuum hose at EGR valve (Buick). On all Chevrolet models except Corvette and on Buick 6 cylinder models, disconnect fuel tank hose at vapor canister. On Buick V8 models, disconnect evaporative emission hose at air cleaner. On Corvette models, remove fuel filler cap.

CO Meter Procedure

1. Connect tachometer to engine following manufacturer's instructions. Start engine and run at fast idle until it reaches normal operating temperature.
2. Connect a suitable CO meter to vehicle following manufacturer's instructions.
3. Place transmission in drive manual transmission in neutral) and adjust curb idle speed to specifications by turning solenoid plunger screw.
4. Adjust idle mixture screws equally to obtain a CO reading at or below 0.3% at specified curb idle speed.

NOTE: If unable to obtain specified CO reading within adjustment range of limiter caps. Cut off tang on each limiter cap, taking care not to damage mixture adjusting screws.

5. Stop engine. Turn each mixture adjusting screw in until lightly seated, then back screws out 4 turns.
6. Start engine and place transmission in drive (manual transmission in neutral).
7. Adjust curb idle speed to specifications by turning solenoid plunger screw.
8. Turn mixture adjusting screws clockwise (leaner) equally to obtain a CO reading at or below 0.3%, at specified curb idle speed, using solenoid plunger to adjust idle speed.
9. Disconnect wiring harness connector to solenoid and adjust low idle speed to specifications by turning throttle stop screw on carburetor.
10. Reconnect wire to solenoid and reconnect vacuum hoses to proper fittings. Install fuel filler cap on Corvette models.

Lean Drop Procedure
1. Connect tachometer to engine following manufacturer's instructions. Start engine and run at fast idle until it reaches normal operating temperature.
2. Stop engine. Cut off tang on each limiter cap, taking care not to damage mixture adjusting screws.

NOTE: If limiter caps have been removed, or if carburetor has been overhauled, turn each mixture screw in (clockwise) until lightly seated, then back screws Out 4 turns on 1 barrel carburetors, or 2 turns on 2 and 4 barrel carburetors.

3. Start engine and place transmission in drive (manual transmission in neutral).

Fig. 104 Lean Drop Adjustment Specifications
See Pic 1

Fig. 105 Lean Drop Adjustment Specifications
See Pic 2

4. Adjust idle speed to RPM specified for lean drop adjustment, Figs. 104 or 105:
a. On 2 and 4 barrel carburetors, turn solenoid plunger screw.
B. On 1 barrel carburetors, rotate solenoid assembly.

NOTE: Do not rotate solenoid more than 1 full turn without disconnecting wiring harness connector to solenoid.

5. Adjust idle mixture screws, turning screws in or out to obtain maximum idle RPM.

NOTE: On 2 and 4 barrel carburetors, adjust idle mixture screws equally.

6. Adjust idle speed to RPM specified for lean drop adjustment as in step 4.
7. Turn mixture adjusting screws clockwise (leaner) to obtain specified RPM drop. Engine should idle smoothly at specified curb idle speed.

NOTE: On 2 and 4 barrel carburetors, turn mixture screws in equally to obtain specified RPM drop.

8. Disconnect wiring harness connector to solenoid and adjust low idle speed to specifications:
a. On 2 and 4 barrel carburetors, turn throttle stop screw on carburetor.
B. On 1 barrel carburetors, turn 1/8 inch allen screw inside rear of solenoid.
9. Reconnect wire to solenoid and reconnect vacuum hoses to proper fittings. Install fuel filler cap on Corvette models.

Let me know.

Joe

So this is a "professionally" rebuilt carburetor on it now?

Are you competent with installing and correctly tuning the carburetor? (What I mean is, are you comfortable and have the tools/ meters to correctly perform the task?)

The Medic

Sorry J & N, I'm slow!

The Medic