This city council can initially structure the municipal government. Once that is accomplished and the city is under the manager form, the power of the council is almost entirely legislative. 65 ILCS 5/5-3-6.
The city council retains ability to control by the power to approve or not approve all municipal expenses and liabilities. 65 ILCS 5/5-3-6. The manager's projects are subject to the council's power over the purse. The council can also abolish offices. 65 ILCS 5/5-3-8.
The final power the council has is that it can fire the manager from office. He/she can be removed at any time by a majority vote of the members of the council. 65 ILCS 5/5-3-7. A wise manager knows how many votes he needs to stay hired.