CHICAGO, NOV. 26 -- The death of Harold Washington, the city's first black mayor, turned Chicago politics upside down even before the city had time to pause for mourning.

Washington, a flamboyant, bear-like man of 284 pounds, had become a larger-than-life figure over the last five years in much the same way as the man he was compared to in death, former mayor Richard J. Daley.

With Washington gone, confusion quickly set in at City Hall and it was unclear today who, if anyone, was in charge. "Buddha is dead," said one alderman. "Everyone has to get out of their head that Buddha isn't here."

Chicago deals crassly with its politicians in life and death. Television anchors here Wednesday were discussing Washington's successor a full hour before he died of a heart attack at age 65. Politicians and hangers-on crowded into the halls outside the hospital emergency room where Washington lay dying.

Dozens more crowded into the city council chambers today for what was supposed to be only a news conference as most Americans sat down for a quiet Thanksgiving Day meal. For the record, all expressed sorrow at Washington's sudden death.

"Turkey and dressing will go down very difficultly for me," said Alderman Timothy Evans, Washington's floor leader in the city council and one possible successor.

But it was clear that the jockeying for power had begun in earnest as would-be mayors buttonedholed aldermen and moved from television camera to television camera.

Alderman Richard F. Mell, who emerged as the leading white mayoral candidate, apologized for the city's crassness. "Chicago is probably one of the most political cities in the country," he said. "Until the Bears started winning, politics was the biggest game in town."

Alderman David D. Orr, who held the largely honorary post of vice mayor, was sworn in as interim mayor this morning in a private ceremony. The 50-member city council next week will choose an acting mayor, who will serve until the next city election in April 1989.

Washington, one of the nation's prominent black political figures, is to be buried Monday following a funeral. His body will lie in state in the City Hall rotunda from late Friday through Sunday.

Washington's death Wednesday at age 65 was eerily similar to Daley's 11 years ago. So was the situation he left.

Both men died of heart attacks during the holiday season, Daley just before Christmas and Washington on Thanksgiving eve. Both spent the last day of their lives at work. Both died at Northwestern Memorial Hospital as the same doctor, John H. Sanders, fought to save them.

And, more important, neither Daley nor Washington left an obvious successor.

Daley's failure to do so led to more than a decade of political warfare that split the city along stark racial lines, which were only beginning to fade at Washington's death. Washington was the third, and most skillful, mayor during that period.

Washington symbolized a different type of politics than Daley, the legendary "boss" of the old Chicago Democratic machine. Daley was an Irish Catholic from the blue-collar Bridgeport neighborhood; Washington, the son of a Methodist minister-lawyer, grew up on the same rough-and-tumble block that housed the infamous Jones Brothers, who ran the numbers racket on the South Side.

He was a product of emerging black political power, and the media politics of the 1980s. In many ways, his election in 1983 paved the way for the election of Mayor W. Wilson Goode in Philadelphia and the 1984 presidential candidacy of Jesse L. Jackson.

Washington ran as a reformer, defeating two Irish Catholics in the Democratic primary -- Richard M. Daley, the son of the late mayor, and former mayor Jane Byrne, a former Daley cabinet member. In the general election, he defeated a liberal Jewish Republican, Bernie Epton.

Washington did not achieve most of his reform agenda. But he became a symbol of black political power and expectations in a city long dominated by a white-controlled power structure.

He governed with a coalition of blacks, Hispanics and white Lakefront liberals. Some in the coalition shared his reform agenda; others, including some black aldermen, joined out of self-interest.

Washington was the glue that held together the coalition. With him gone, it is unclear what will happen to it. According to the 1980 census, 40 percent of the city's population is black and 14 percent is Hispanic.

There are 18 blacks on the city council; 26 votes are needed to elect the acting mayor. Mell, who represents a largely white area on the city's northwest side, said today that "the odds are on" a black succeeding Washington, but it is "not an absolute."

Evans, who was Washington's chief political spokesman in the council, and Alderman Eugene Sawyer are the leading black candidates on the council. But neither has solid credentials as a reformer, nor is widely known. A third black, Alderman Danny Davis, has expressed interest in running.

There is also the possibility that someone not now on the council could become a candidate.

City Treasurer Cecil Partee, far better known than Evans or Sawyer, is said to be interested. Chicago Sun-Times political columnist Basil Talbott Jr. speculated that Democratic presidential candidate Jackson, long a Chicago resident, might consider the same possibility.

But the Rev. Willie Barrow, a longtime Jackson aide who was watching out for his interests at City Hall today, said Jackson, now in the Middle East, is interested in being president, not mayor of Chicago.

Amid all the jockeying, three of the city's best known politicians sat quietly on the sidelines. Any one of them, or all three, could become major players in coming weeks.

They are former mayor Byrne, State's Attorney Daley, and former county Democratic Party chairman Edward Vrdolyak, who led anti-Washington forces in the city council for four years before running as a third-party candidate against Washington in April. Vrdolyak recently switched parties.