Carter-Webber's

Have a quick question, Need an emissions expert probably for this one, but My subaru brat is currently powered by one of em carter-webber carbs that everyone hates... Are thoes carbrators adjustable in the air/fuel mixture? From the looks of the results it's running just a tad rich, the car has a new air filter, cap, rooter, spark plugs, and spark plug wires, tuned to 8 degress btdc. purrs like a kitten, but here are the following results it gets from emissions testing. Cruis RPM is 2,500 and the idle rpm is something like 950, a little high I guess, but it wasn't over the limit. Heres how it did. Hydrocarbons, limit at cruis or idle is 220ppm at idle it failed at 226ppm, at cruise it passed at 64ppm. CO % limit is 1.2 at idle, it was 2.19, at cruise it was 1.72. so obviously it failed the co % CO+CO2 % minimum at cruise is 6, it passed at 15.62 with an "N/A" Idle, minumum is 6, it was 15.29. O2 % was 0.7 at cruise, no limit, and 1.32 at idle, no limit. so thats the results, and it failed the CO % at idle and cruise and it failed hydro carbons or (HC) at idle... first time I tested it with all the vacume leaks, it ONLY failed the hydrocarbons at idle, but it was at a very high rate, at idle it was about 1024ppm and the limit like I said earlier, is 220ppm. Anyway any help would be great, if all else fails, I'm gonna just take off the intake manofold, put on a hatachi carb and intake, and remove all the emissions garbage, and according to Austin, it'll pass that way. Anyway any info regards to what Might be wrong and why it's failing the way it is, and how it can be fixed other than replacing the top half would be much apreciated, thanks everyone!