Whenever a capital outlay fund is established, it shall be used only for such purposes, except the board of directors may, by a four-fifths vote of all members, if it finds that the fund is no longer necessary or that there remain in the fund moneys which are no longer required for such purpose, discontinue the fund or transfer so much thereof as is no longer required for capital outlay purposes to the repayment of any bonds outstanding, or if there are no bonds outstanding, to any fund used for the payment of current expenses of the district.