Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Electric Choke Issues?

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TravisUT:
Hello, new member here; Apologies if this is a duplicate post! I'm having some issues with my carb and was wondering if anyone could help.

I have a Quadrajet 4 barrel (17080212-1024), mounted to a stock intake on an 84 C20 454. I recently replaced the hot-air choke with an electric choke, and since then, almost every time I start the truck, I get wet black spatter shooting from the exhaust pipe, along with some fuel-smelling smoke. Once the engine warms (choke opens very quickly), the smoke clears and the truck runs great. With the hot-air choke, this problem didn't happen. Also, I recently replaced the spark plugs (they were all fouled, very carbon coated). I don't know if the fouling was just since the electric choke was put on, or if it's been running rich for the last 3 years (since engine and carb rebuild). I've tried adjusting the air/fuel mixture screws, based on RPM, but that didn't seem to help much.

Should I go back to the hot-air choke, or what can be done? I'm not a mechanic, but am comfortable with working on the equipment.

77cruiser:
Sounds like the pull off isn't opening the choke on start up. It should open about a 1/4 inch on start up.

quadrajam:
Some items to consider...  The hot air choke had some built-in idle air bypass by design.
You may not have that going on now with the electric choke. Did you change the choke housing
or just the bimetalic coil/cover? Do away with the hot air tubing?
Make sure the loop in the bimetalic coil engages properly with the peg inside the choke housing.
Crack open the throttle and make sure you can twist the black cover and move the choke both directions. Dont reuse the housing gasket and source the choke power from key-on.

That carb should have a rear and front pull-off. The front pull-off also controls the secondary
air valve. Never been a fan of any of the rear pull-offs.I would remove it for now and just
use the front pull-off. Make sure it cracks the choke about a 1/4 inch as 77 mentioned.

QJ

TravisUT:
I just changed out the coil/cover, and did away with the hot air tubing. I still have them though. I will be checking the pull-off's today! In regards to tuning/adjustments: what is the best order to make the adjustments? Should I do the fast idle, primary pull off, secondary pull off, and then choke adjustment, in that order? Or a different order? I'm worried that one adjustment will mess up the other...

quadrajam:
I assume the pull-offs tested good....?
Prop the throttle open a little bit so it doesnt interfere, Rotate the choke cover back and forth
to make sure theres no binding,turn it til it just closes and tighten it down. Apply vacuum
to the front pull-off and it should barely crack open. Note that you can push it a little
more open with your finger due to the normal slop in the link. This is where you want the 1/4 inch
 gap mentioned before. there is a spring loaded phillips screw on the pull-off to adjust this.
When you  crank it up you will have to work quickly back and forth with the speed screws
and it will take several cold start cycles to get it dialed in.

QJ

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