NordicSeven

Does anybody have good instructions how to lower down CO and HC emission figures? My 12A engine has those rather high, I just and just managed to pass emission test last week. Also O2 figure was rather high.
In my understanding CO figure can be somewhat adjusted with Idle mixture screw in the carburator, but what about HC? Before getting the carburator adjusted, I would like to understand what other things might be wrong?!

There is the emission control system in the car, including air pump etc., and I guess it should reduce CO and HC if working correctly!
Everything in the emission control system should be standard eguipment - no modifications done. Here in Europe those 85' 12A engines are still using the older type (=less connector pins) emission control unit, no catalytic converter etc. included either.

Could e.g. excess oil delivery from a faulty metering oil pump cause too much burning oil and thus extra emissions, or e.g. could problems with ignition cause this? There are also several valves included in the emission control system - could some of those cause this?

The engine is recently rebuilt, and sounds to be working fine otherwise. There were high emission figures already before the engine got broken, and they seem to have remained more or less at the same level even all seals etc. have been replaced. An older emission test result some years ago shows much lower figures - so something has changed meanwhile!

Any good advice how to fix these problems?