Mercedes 220 Engine work

Our objective is to investigate the poor running of our 1953 Mercedes 220 engine. Already, we have discovered a defect in the carburettor. As you can see from the images below, we have laid a flat edge across the top and one edge shows a slight concave whereas the other shows a convex. This should be completely flat and these are very minor but enough for the carburettor to be operating with a weakness.

We have now stripped the carb and flattened the edge all over to remove the imperfections before rebuilding.