Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

7029207 transition too rich

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bob69:
Cliff, in all of the testing I've been doing with the 7029207, I've noticed that the afr's in the 1000 to 1500 rpm range have been on the rich side. No matter which jet/rod combination I use the afr's in this transition range are in the low 13s. Even when the idle afr's are set to the 14 range the 1000 to 1500 rpm are still in the low 13's.

The 7029207 is known to have generous idle fuel. But what if your combination does not need the extra fuel. Is there a way to reduce the fuel flow in this off idle range. 

Cliff Ruggles:
Are you noticing negative running symptoms thru transition or just watching a gauge?

There were several different "recipe's" used on the 7029207 carburetors depending on if they were original units or Service Replacement. 

When used outside the original application (350/350hp) you may need to install slightly smaller idle tubes and or DCR's to clean things up at idle/off idle.  I've had to do this a few times when 7029207 Service carburetors were being used on the 350/300hp or engines with smaller cams in them.......

bob69:
Cliff, drivability is OK but I would like to increase gas mileage. I have a 50 mile pleasure drive that I make often. Speed averages between 35 and 45 mph. The car burns around 3 1/2 to 4 gallons of gas - mpg around 13 - 14 mpg.

Gas milage should be a lot better with a mild sbc 350, 200r4, 3.55 rear. Engine rpms are in that 1100 to 1500 range.

bob69:
The 7029207 is a service replacement carb. The date code (2602) suggests it was made in 1982.

77cruiser:
Not likely to do anything with the AFR, but do you have working vacuum advance?

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