I have just bought a 1988 Accord Aerodeck 2.0L carb (non cat, Automatic) When the car is cold it starts well but won't fast idle. It idles at about 500rpm and judders like mad until it's warm. Once warm it idles fine, lovely and smooth. Even if the car has been left for a few hours the same problem occurs. I have checked the choke butterfly and this is opening and closing fine as the car warms or cools. Is there something else which kicks in to make the car idle at the right revs when cold? I'm stumped.
Regards
Nick

 

The parts drawings I can post don't do it justice - you can't see enough detail. And the USA vs. UK carburators might just be different in the little details.

Work the choke plate with your hand. You should notice a cam & linkage that connects to the throttle shaft. There's usually a screw that holds the throttle open a small amount when the choke is closed. When the choke is open that screw won't push the throttle any more. Sounds like that screw needs to be adjusted to open the throttle a bit more.

 

Thanks very much. I think this is the problem. Just trying to get it right now when the engine is cold and hot. Thanks again. Adders