(2) Warrants so drawn in excess of the cash on hand in any such fund shall be stamped "Not Paid for Want of Funds" by the city treasurer, shall bear the legal interest from the date of such indorsement until the date of payment and shall be paid from the current receipts of the plant or system. The warrant indebtedness shall not be considered or construed to be within the charter limitations respecting any municipal debt.
(3) Warrants issued pursuant to this section shall be retired in the order of their presentation for indorsement "Not Paid for Want of Funds" as funds are available.