It's been a few years since I've build a Carter BBD but my car has been running rough lately so I thought I'd throw a kit in it. Not sure what I did wrong but the car doesn't want to idle below something like 1300rpm and it kind of surges now. Definitely not in a drivable state.

The only adjustments I made were float, step up piston, accelerator pump and bowl vent adjustments.

For the float I turned the carb over and adjusted the float so it was 1/4" from the crown of the float to the surface of the fuel bowl. That one seemed easy enough.

For the step up piston I put the carb back together, pressed the step up piston all the way down and then put moderate pressure on that plastic tab while I tightened the screw.

Accelerator pump I put the idle screw at curb idle, set the accelerator pump so it's 1/2" from the top of the "air horn" as the service manual states. I set the pump so it was 1/2" from the lip of the carb where the red arrow in the picture is pointing. Is this correct?

Bowl vent had me slightly confused. Service manual states there should be an .080" gap between the bowl vent valve and seat. Does this basically mean the bowl vent should be .080" open while at curb idle? If so, as you can see the lever the green arrow is pointing to in the picture is not even touching the plastic piece, so it looks like it's closed all the time. Is the adjustment asking me to bend that lever down to make contact with the plastic so the bowl vent is open .080" at curb idle?

I'm thinking it's an accelerator pump issue but I feel like that adjustment was pretty straight forward. What do you guys think could be causing this? Thanks.

This is a symptom of a vacuum leak. Surge can be caused by lean mixture.

Re check float level, rod adjustments, and vacuum leaks around base of carburetor. Also take a look at how taught throttle cable or linkage is, and is it allowing throttle plates to fully close.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I bumped the idle speed up as far as it would go so it would idle on it's own long enough to take a vacuum reading. I was getting about 14hg on the gauge which I didn't think was so bad for as fast as it was idling. I'll have to take it apart again tomorrow to see if I missed anything.

Is the adjustment asking me to bend that lever down to make contact with the plastic so the bowl vent is open .080" at curb idle? Yes. The picture in the manual is not very clear.At curb idle that plastic should push that lever up opening the vent. Just off curb idle plastic should drop closing the vent. Measure at valve itself between rubber and side wall of carb.

Check the new gasket between throttle plate and carb main body.It could be restricking flow in the idle channel. The sealing surface close to idle channel is narrow, an air leak there would lean out the idle.

I agree with matv91, most carb kits have multiple gaskets for each part of the assembly & you have to (carefully) match up the new one to the old one. If you have the wrong gasket for the throttle base or venturi cluster- that'll mess up the idle circuit.

Or you knocked some crud loose during the overhaul that wasn't fully flushed out. I can't recall how many carbs I've had to pull a second time, blow out the passages with cleaner & compressed air (again) before it'd work OK (I never have actually seen that bit of crud- it must be metaphysical or something).

Unless you have a very rowdy cam or live at high altitude- 14" vac is pretty bad. A stock engine might have 18-20" at idle near sea level. That reading will usually remain steady or increase another inch or so as you slowly rev the engine up to 1500-2000 (no load). Low vac could be caused by a big vac leak, lean condition, or late/retarded timing.

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63 Valiant Wagon
225 - 4 bbl

Thanks guys it turned out to be the carb gasket between the throttle plates and main body as matv suggested! I took everything apart, put the correct gasket in and it started up and ran just fine. Thanks a bunch.