Yesterday I did my car test for the license and the emissions were over the limit. The guy testing the car told me that there is something in the carburettor that can be adjusted but there is a seal that needs to be broken, so he didn't want to do it himself. Is this the right way to go about it or is there something else that is the root of the cause?

it can be, when the mixture is not correct it will go to high on your emmisions.

mayby take it of and rebuild it? or take it to a rebuilder?