Andy Young heads into Tuesday's mayoral runoff as a front-runner hustling for votes under a storm cloud of racial bitterness seeded by his chief supporter, Mayor Maynard Jackson, who referred to blacks backing Young's white rival as "shuffling and grinning . . . Negroes."

Until now, the issue of racism has been among the most dominant, if least openly discussed, issues in the campaign. The white business community scouted quietly about for months for a stalking horse to recapture city hall after eight years under Jackson, who is black, and finally settled upon Sidney Marcus, a white state legislator with biracial support and a reputation as a liberal.

But the black mayor of this bustling city billed as "too busy to hate" has now been accused of throwing the same kind of racial curve ball to get blacks to vote for Young that southern white politicians so often use to scare out their vote.

"It reminds one of the kind of thing George Wallace said in his heyday," said Charles Black, a black campaign manager for Marcus. "If a white candidate had made the same statements, it would only be construed as racism." And black supporters of Marcus have begun needling their rival camp with bumper stickers proclaiming: "Shuffling Grinning Negro."

Young has acknowledged that "race is clearly an issue; it always has been an issue in the campaign. But I've always agreed with whoever it was who said that racial need not be racist. If everybody's concerned about the racial factor, and I think they are, then I think it's important to discuss it openly."

Young took 41 percent of the vote to Marcus' 39 percent in the Oct. 6 general election, with 16 percent going to A. Reginald Eaves, a black Fulton County commissioner who has endorsed Young. There was some racial crossover in this majority black city, with Young taking 12 percent of the white vote, and Marcus 9 percent of the black vote.

But Jackson kicked the lid off more than a week ago when he told 120 blacks at a downtown YMCA luncheon that some white business leaders are determined to have a "white mayor." He labeled blacks behind Marcus who believe a white mayor would do more for blacks as "Negroes" who are "shuffling and grinning around the campaign of" his opponent.

He accused them of "selling out" the civil rights movement, and likened them to "these slick-talking Negroes trying to justify their relationship with the Reagan administration, jockeying for positions closest to the table so that when the president is reminded to throw them a crumb, they will be in a position to grin and catch it."

Jackson usually refers to blacks as "Afro-Americans" as a term of respect, never "Negroes."

Such comments not only disturbed Marcus' supporters, say campaign observers, but also partially backfired, solidifying support and wooing new backing from others in the black community who perceive City Hall as the court of Atlanta's thriving black bourgeoisie.

"I would rather have him call me a nigger," said state Rep. Douglas Dean, one of Marcus' most outspoken black supporters, calling Jackson's remarks "worse than slave plantation politics . . . an attempt to control black people's minds." He said he believed Marcus' relationship with rural state legislators would yield more jobs for Atlanta blacks than Young could produce.

"When you talk about pride, a black mayor is not what gives you pride," he said. "Mama and Daddy having jobs is what gives you pride. If blacks don't build a relationship with the business community and if businesses continue to leave Atlanta because of poor relations with city hall, blacks are the ones to be hurt."

Marcus accused Jackson of anti-white "race-baiting" and demanded an apology. "I was absolutely shocked that he would take eight years of pulling this community together and destroy it in 10 minutes," he said. He then roasted Young for not repudiating the mayor and accused him of "race-baiting" by proxy.

Young said the mayor was "not speaking for me. Neither do I tell him what to say."