The charter shall specify a mayor or city manager who shall be the chief administrative officer and the head of the administrative branch of the city government, supervising the administrative affairs of the city and carrying out the policies enacted by the elected body. He shall enforce the ordinances of the city, the charter, and all general laws applicable to the city. He shall keep the elected body informed of the condition and needs of the city and shall make such reports and recommendations as he may deem advisable and perform such other duties as may be required by charter, ordinance or resolution of the elected body. He shall have and perform such other powers and duties not inconsistent with the provisions of the charter as now are or may be conferred or imposed upon him by municipal ordinance or upon mayors or city managers by general law. The city manager shall have the right to take part in the discussion of all matters before the city council, but not the right to vote.