On a day to be fixed by the council but in no case later than the twentieth day of August in each year, the mayor shall submit to the council:
(1) A separate current revenue and expense budget for the general operation of the city government, to be known as the "general fund budget";
(2) A budget for each public utility owned and operated by such city;
(3) A capital budget; and
(4) A budget message.
When submitting the budgets to the council, the mayor shall submit his recommendation of new sources of revenue or manner of increasing existing sources of revenue, sufficient to balance the budgets, if such additional revenue is necessary to accomplish that purpose.