[Paulporsche]

I can't tell where you are located, but if you don't need to pass a smog test, the recommended CO is 3.5% (per JW).

Without a meter, you can still get a good setting, even though you don't know the exact figure by raising the sensor plate in the mixture control unit while @ warm idle, which it sounds like you have done. If the revs rise you can go richer. If lowering the plate makes the revs rise you can go leaner. If you raise the plate and if you lower the plate and the revs fall then you are OK.

If, after warmed up, you get a fluctuating idle you are too rich. Set the mixture back a little leaner. If you get any popoff valve popping, you need to enrichen.

If, after this, you are still having warmup idle problems, you need to check your WUR and AAR.