President Carter today sought to turn the potentially damaging consumer price index figures to political advantage by warning voters not to buy Ronald Reagan's proposals for an across-the-board tax cut.

Carter acknowledged that the 1 percent jump in the index was evidence of strong inflationary forces in the economy, adding that Reagan's proposed tax cut "would be like pouring gasoline on a fire."

The president said that his proposal for a tax cut next year, weighted more heavily to business than is Reagan's, would not be inflationary.

In a prepared text of his opening remarks at the Knights of Columbus hall here, Carter said, "Most people recognize that fighting inflation is not easy. It requires patience."

Reagan has tried to build his fall campaign around the economic issue, charging Carter with failure to control inflation or unemployment. Carter has avoided disucssing the economy during most of the campaign, concentrating instead on the war-peace issue. But with today's inflation figures, there was no way he could avoid it, and he decided to attack rather than be put on the defensive.

On election day, Carter said, voters "must choose between my policies, which will build our country's economic strength and actually work to reduce inflation -- that lay the foundation of a true economic renaissance in America -- or those which will squander our hopes on economic voodoo."

The president also took a slap at the Rev. Ralph David Abernathy, Charles Evers and other black leaders who have endorsed Reagan.

"Actually, they are former black leaders. They're not black leaders now," Carter said. He pointed out that Abernathy once headed the Southern Christian Leadership Conference, but that the present leader, the Rev. Joseph Lowery, endorsed Carter Thursday.

Carter's campaign stop here before flying on to a campaign appearance in Gerald R. Ford's home town, Grand Rapids, Mich. -- where he took questions from 25 high school seniors and their parents -- provided a new variation on the meetings with small groups of citizens that have become a staple of his reelection campaign.

The president was invited here by Catherine and James Rafferty, and the roughly 55 persons seated around him in the Knights of Columbus hall were relatives or friends of the Raffertys.

These invited guests who put questions to the president were far outnumbered by the reportes and cameramen recording the event.

Meanwhile, several thousand people filed the sidewalks of Monmouth Street outside the hall, cheering Carter as he passed and waving American flags.

The crowd was enlarged by the nearby Mary Ethel Costello School's decision to release its students early for the president's appearance. The school also distributed the American flags.

Carter also misstated one of the elements of the economic policy package he proposed in August. The president said that he advocates the removal of the "marriage penalty," which requires a working husband and working wife to pay more income tax then they would if they had the same income but were not married. Carter's economic plan, however, calls for only a partial easing of that penalty.

The president followed a pattern of many of his recent campaign appearances by seeking to wrap himself in the tradition of his Democratic predecessors in the White House. Carter said: "We are in the history and the theme and commitment and principles and ideals and tradition of Franklin Roosevelt, Harry Truman, John Kennedy and Lyndon Johnson . . ."

In heavily Irish and Italian Catholic Gloucester City, where Carter was appealing to the media audiences in New Jersey and Philadelphia, the president tried to soften his opposition to tuition tax credits for parents of parochial school students by saying "we will go ahead and continue to increase the allotment of federal funds for the parochial and for the public schools."

Carter was warmly received, but he also wasn't taking any chances.

In reckless disregard of his electoral prospects in Kansas City and Houston, Carter kept a red and white Phillies cap on a stool by his side as he answered the groups's questions.

At the end, he donned the cap of the new world baseball champions.