After submission of the budget by the City Manager, the Council shall review it in such detail as it deems necessary, and after a public hearing held not less than 10 days after public notice thereof, may revise the budget in any manner it finds necessary. Not later than the last day of the fiscal year the Council shall adopt a budget for the ensuing fiscal year, failing which the last fiscal year allotments shall be effective until the budget is adopted. From the effective date of the budget, the several amounts stated therein as proposed expenditures shall be and become appropriated to the several objects and purposes therein named.