As Sterling Tucker lunches in the middle of Mel Krupin's restaurant on Connecticut Avenue, a carrousel of important faces circles to pay respects--mostly from a distance.

The Rev. Gilbert Hartke of Catholic University slaps the former City Council chairman on the back, then sits at another table. A wealthy woman who contributed to his last campaign for mayor gives Tucker a quick kiss on her way to the ladies room. Former National Urban League president Vernon Jordan says he'll have lunch with Tucker sometime; lawyer Joseph A. Califano waves from the steps.

No one stops. There are no promises of campaign contributions or of support for the man who was barely beaten at the wire in the 1978 Democratic primary for mayor and now says he wants to run again.

In the past year, Tucker has become a regular sight at Krupin's, eating with the lawyers, developers and other businessmen whose contributions have been known to make or break political campaigns in the District of Columbia, trying to get them to put their money on him one more time.

Tucker has had a lot of lunches, but no luck. The man who raised the most money in the 1978 primary hears only that he should forget it. The word is that he cannot win, he says, and no one wants to give time or money to a loser.

"What kind of sport is this, one strike and you're out," Tucker complains. "I'm a good person and I can lead. Even in games people are more sensitive to talent. I can't understand what's going on . . . Why? Why?"

"No one won that last election," he adds, "it was a fluke, you know, that's all, a fluke."

Tucker, 58, lost the 1978 contest by exactly 1,500 votes, due in large part, observers say, to a poor performance in 11th-hour debates, a last minute effort to get Barry out of the race that backfired, an aggressive endorsement of Barry by the editorial page of The Washington Post and a Tucker campaign organization that faltered in the clutch. Tucker did not concede defeat for two weeks, and then only after contending that the vote count had been a farce.

But as Tucker plans a second run for mayor, the money-men who supported him as an incumbent council chairman and a candidate who led in all the polls are keeping their distance.

"I, like other people all over town, am trying to discourage him from running," says Raymond J. Howar, a realtor who was on Tucker's campaign finance committee in 1978. "I haven't told him yes or no yet. But he should know the answer is no. He's got a loser image. He's out of the mainstream, not involved with the city . . . "

Tucker alienated many of his old supporters by never calling to say 'Thanks' after his defeat and by not staying in touch. Others still grumble about Tucker's lack of attention to his campaign strategy in the last race and the way he ignored the advice of some.

A number of his key advisers are gone, too.

Joseph B. Danzansky, the former president of Giant Foods Inc., a major contributor and political adviser, is dead. Lawyer Robert B. Washington Jr., former head of the city's Democratic party, was Tucker's chief campaign strategist in 1978. This time around, he has been among those urging former Carter cabinet member Patricia Roberts Harris to run for mayor.

Bailey-Deardourff & Associates, Tucker's political advisers in 1978, are already signed up to work for City Council member John Ray's campaign for mayor. Del. Walter E. Fauntroy, who endorsed and actively campaigned for Tucker in 1978, has been mum on this year's mayor's race. Harley J. Daniels, a lawyer who was in charge of election day operations for the Tucker campaign, has jumped aboard the Barry bandwagon.

"Marion did a good job and deserves to be reelected," Daniels said recently. "Personally, I believe Sterling has a lot to contribute to the city, but not as a candidate. It doesn't make sense for him to run, particularly with Patricia Harris in the race. She's a new face and she goes to the same people that Sterling would ask for support."

"We worked our hearts out in '78," Daniels reminisced. "We had the opportunity to win. We should have won. It was the right time, but we didn't make it. Seventy-eight is history, but Sterling won't forget it."

Tucker turns a deaf ear to the talk of him as a loser. "The Sterling of old wouldn't be running," he says over lunch. "The Sterling of old would have said he'd heard from some people and they won't contribute . . . So he'll go off and do something else. The new Sterling is not going to let a cadre of money people determine whether I have a chance to reach my peak."

Tucker says he plans to find new financial backers. That's what Barry did in 1978, when the standard money sources were cold toward him. Barry tapped a new breed of political contributors--young professionals in real estate and law--to finance his victorious campaign.

"If you travel the same old political paths you'll find the same old political types scurrying around trying to make sure they're on the right bandwagon," he says, his reserved manner and low voice taking on an even lower, even more resigned tone. "That favors the incumbent.

"But there are new paths to be created, new roads to be trod. People are reaching out to me to save the city and I am answering them." A woman at the next table, hearing Tucker talk about the race for mayor, turns toward him and asks with surprise if he is really running.

Tucker nods. Immediately, a man at the woman's table volunteers his help. Tucker reaches over, shakes the man's hand and looks him in the eye. "Will you really call?" Tucker asks.

If Tucker were to pull out of the race it would simplify matters for the financial contributors as well as his potential opponents. Tucker's absence could allow middle-class, older Washingtonians to solidify their support around Harris, who as secretary of Housing and Urban Development gave Tucker a new job right after he lost his bid for mayor.

His withdrawal also would begin to narrow the field of major candidates that now appears to include Barry, Harris, Ray and councilmembers Betty Ann Kane, John A. Wilson and Charlene Drew Jarvis.

Tucker sees Barry the mayor as a failure.

"The record of the last three years is a record of leaderless government, stumbling, uncoordinated, without direction," Tucker says. "It's a now-you-see-it, now-you-don't government with its constantly changing facts and figures. It's a government that is opportunistic and political to the detriment of the people of the city . . . He's using the public treasury as a campaign kitty right now."

The only recent exposure for Tucker, former longtime president of the Washington Urban League, has come with the Operation Rescue program to tutor public school students in danger of failing. The program continues to be a success but it is no longer a new effort that attracts the limelight.

He served as an assistant secretary for Housing and Urban Development in the Carter administration and now operates his own consulting firm, Sterling Tucker & Associates.

He has a $19,950 contract with the National Capital Planning Commission to improve their relations with public officials and citizen groups and he tried to put together a deal between a small, black-owned caterer and a major food service company for the food concession at the Washington Convention Center but failed.

The setbacks don't discourage Sterling Tucker. After leaving Krupin's with a reporter, Tucker walked up Connecticut Avenue towards M Street and the building where his new office is located.

"Nice office, isn't it?" he asks. "High rent district, right? I must be doing all right, right?"