WHAT IS THE PROPER PROCEDURE TO ADJUST AIR/FUEL ON 4 BARREL CARBURETOR WHICH SIDE IS FUEL? WHICH IS AIR?

1985 Chevrolet Custom Deluxe

Tiny

GTech7

October, 28, 2011 AT 11:59 PM

Vehicle would not pass emissions I believe mixture was too rich. Heavy smoke on exhaust RPM's are about 6500. The idle set screw was turned down the fuel air adjustment screws were tightened finger tight (so as not to cause damage to carb) and vehicle was started starting with passenger side at 1/4 turn increments counter clockwise the screw was turned until engine started to die then turned back clk wise until it ran better. Same procedure was done to right side of carb (Note not a holly carb) still heavy fuel smell during adjustment and exhaust smoke was heavy with smoke. Vehicle failed emissions twice but second time it went from 1200ppm-505ppm high end is 300ppm of hydrocarbon emissions and the CO% is 6.04 and tolerance is 3.00 how do I correct this so the vehicle will pass?

FOUND 720 RELATED QUESTIONS

1 Answer

Tiny

Jacobandnickolas

November, 3, 2011 AT 2:41 AM

Take both in the entire way. Turn them out 1.5 turns each to start. From that point, you need to adjust them slowly until the engine idles smoothest and right before the RPM's start to go down.

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