I recently rebuilt my carb. Now the mechanical choke slams the choke plate closed and floods out the carb. I am also having a challenge tuning the mixture screws. Any suggestions. Thanks guys

HI cagle,
The choke adj. is set to harsh. Back off the adjustment on it so that it barely closes when cold. (without the engine running). Once it lazily closes as you pull the throttle open that will be pretty close and as it warms it should slowly open all the way by itself too.
Slamming shut as you mentioned is way to tight of a setting, thats why they are adjustable.
Others might have some other suggestions but that is my 2 cents worth http://www.camaros.net/forum/smile.gif

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.... Jim aka Click
69RS 350/255 LM1, TRW forged pistons, .30 over, TH-350 auto.,
Dover White, Blue Vinyl top, F&R spoilers, am/fm, 3.08 Posi.
A/C, fold down rear seat, Pdb, PS, Cowl Induction, Endura Bumper
My RS.. www.brainerd.net/~knudsen/69RS (http://www.brainerd.net/~knudsen/69RS)

Hi Cagle
You might check the choke unloader to make sure the diaphram is not punctured. This device sets on the pass side of carb and has linkage from the choke plate to its actuating rod. The unloader will have a short length of vacuum line going to the base fitting underneath.

You may want the choke to slam shut, then when the engine starts and creates a vacuum, this choke unloader pulls the plate open against the heater spring. As the bimetal spring heats up, the unloader pulls the choke open. Look through the instruction sheet w/overhaul kit for opening measurement of the unloader device measured at the air horn to plate.

Once the engine starts, and choke is pulled open by the unloader, if you have a divorced choke, meaning the heater is in the manifold, you might be able to bend the heater linkage to open (lean) or close (richen) the choke setting to smooth out the engine operation during warm-up. If you have an intregal choke, one with the heater on the side of the carb, loosen the three screws and rotate the plate lean/rich ro smooth engine operation.

Set fast idle for 1600-1800 rpm. Allow the engine wo come up to operating temp, drive the car for 10-15 miles and return to driveway. Open hood, remove air cleaner, attach a vacuum gauge to a base fitting, full time vacuum, and adjust the idle mixture screws for a maximum reading with the vacuum gauge. You will rock back & forth between the two screws. You're looking for a steady needle indicating 18-20 inches at 600-750 rpm. Just remember, the more you close the primary throttle, the more affect the mixture screws will have in engine performance.

Should be a smooth transition from idle rpm to say, 2000 rpm. You may have to unscrew the mixture screw a 1/4 turn each to help make up the stumble or bog. Check ign timing with timing light and make adjustments if needed.

Sorry for the long post, but, you didn't give us much info to go on, had to cover both applications plus other adjustments

Click did a good job
Good luck....

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Everett "OBJECTS IN THE MIRROR APPEAR QUICKLY UPON RAPID DECELERATION"

ffcagle34 this is a link to a thred i had about tuning my qjet, its very informative, also do a search for some of my posts, a while back i was working on my qjet and got all the answers here. http://www.camaros.net/forum/Forum16/HTML/001517.html hope this helps you

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1984 Chevy Camaro (305)