I had/have same issue, i even strted a thread with no success. I have same lame ultra rich 10s' readings too. I tried what gtjosh if i remember correctly said changing the triangle part (enrichment chamber) with no success. Carb has been cleaned numerous times, it looks spot on too. Can't really address the issue anymore. It's annoying as hell, it's expensive as hell (consuming that much fuel at little or no boost-wtf?) AND is making the car actually slower. In between gears and at low-middle revs the car is laggish like hell and really slow compared to how it was some years ago before the problem pops up.
Yes i know i didn't exactly give any solution, but wanted to inform you that there are others out there with same problem
Ohh almost forgot . The ultra rich afr problem lead to my piston rings going off. Now except the excessivce fuel consumption i have excessive OIL consumption too