Dual Carter AFBs getting in to the fast idle circuit quicker

2 Carter Afbs on a stock intake, have to crank for a bit then pump gas quite a bit but the car does eventually fire up. Choke seems to work fine on back carb.
The question is, how do you get the carbs get on the fast idle circuit quicker?
It runs a little rough because the idle is low.
It eventually gets there to idle around 1500 cold but it's not as quick as it should.
Does the dash pot need adjusting.
Fast idle screw seems to be in quite a bit.
There's something going on and I'm missing it, on the back carb. 1969 carbs

If the choke is fully closed, the fast idle screw is on the high step of the cam. Once you pump it to set the choke do not hit the throttle. If the vacuum pull off (dashpot) is adjusted so it pulls the choke open to far, then the next time you hit the throttle it'll knock the fast idle cam down a notch or more. Are the bowls full when you go to start (electric pump?). If not the modern fuels evaporate quickly. The bowls may be empty. No electric pump? Crank the motor to fill the bowls. Then set the choke with one pump. It should start right up and fast idle.
Doug

Thanks that's exactly how I am going to do it.
I'm doing it wrong.
When I pump the gas a few times , I'm knocking the fast idle off a notch. Guaranteed. I did play with the dash pot, which way would you go to get the choke to open properly?
Up or down on the dash pot? Thanks

The pull off only needs to open the choke far enough to keep the engine from loading up. I'd start with an 1/8" drill bit held vertically against the inner choke wall. Set the pull off so the choke blade just touches the drill bit when there is vacuum applied. If it loads up open it a 1/16". If it stumbles with the choke on close up the clearance a little.
Doug

Load the vacuum pot by holding it down with your finger and not touching the arm. With the advent of the fuel injection age we forget how it was taught, one push to set choke then foot off the pedal. If bowls are empty (week or more) crank over a few turns. Most of the factory service manuals have instructions on setting the carb for fast idle-startups

Just like Doug says. Even if you pump the pedal 4 times dont start the car until you stop pumping the pedal and on the last pump be sure to push the pedal at least half way down so the choke still sets. Most cars that have a good pump shot only need the gas pedal pressed to the floor once and then release the pedal and start the car. It will be on the high step of the fast idle cam if everything is adjusted right. Then after it starts you can tap the gas in a minute or so and it should drop to the next step on the cam if the choke pulloff is adjusted right. With two carbs you may need to pump it a few times to start. Like Doug said if it loads up when started check the choke pulloff adjustment so its not to rich. Ron