I would say at a guess your fuel pressures could be wrong.

If you have access to a fuel pressure guage, connect it between the feed from the metering head to the warm up regulator, get the car warm, ( by running it for a short time), then bridge your fuel pump relay so that the pump runs continous, with the ignition on and pump running you should have a controlled system pressure of approx 3.5 bar, then if you block the pipe that goes from the warm up regulater to the metering head( its next to the tank return union on side of metering head) the pressure should if all is working correct go up to approx 7.0

if either of these are out of range, ie not enough pressure the K jet system over fuels, and no amount of tweaking the CO% will cure it

If you have no control pressure there are two ways you can fix it, first is to replace the warm up regulator with another known working example, then re test the system as described above.

Or

Replace the warm up regulater with a different pressure regulater, a 2wd Cosworth item will be best as that runs at approx 3.5, and has push on hoses so can be easily fitted to you system, but this will affect cold starting a little, but shouldnt be that noticable

hope its of use to you.