First time I've posted on this forum and I'm looking for some advice on setting the idle on my 1989 Mini Mayfair 998. It has a single HS4 carb which idles too high even though the idle screw is screwed right out so there's no more adjustment and the butterfly appears to be fully closed. The is also some slack in the throttle and choke cables and I'm unsure if the mixture screw can affect the idle speed to this extent. I've checked for air leaks and found nothing obvious. Starts fine with the choke and when the engine settles it just idles a bit too fast and there's nothing left to adjust it slower.
Any advice will be much appreciated.