The U.S. Ambassador to the United Nations, Andrew Young, said yesterday that he could "almost guarantee" that Congress will repeal the controversial Byrd amendment that permits U.S. imports of Rhodesian chrome.

Young, speaking shortly after his arrival in this former slave trading center on the first stop of a fact-finding trip to Africa for President Carter, also said that he believes an agreement is possible on the peaceful transition to majority rule in Rhodesia.

"I don't like to think of the Geneva conference as stalemated," the black envoy said of the apparent breakdown of the Rhodesia talks in Switzerland. "I think we are two-thirds of the way toward developing a scenario that both blacks and whites can live with."

The former U.S. congressman from Georgia, whose outspokenness has led to differences with the State Department, said he could "almost guarantee" repeal of the Byrd amendment "within 30 to 60 days" because of a changed climate in the United States.

In an interview with The Washington Post before he left New York, Young said his credibility and U.S. credibility will be preserved "if I can deliver by March on repeal of the Byrd amendment; if by July we could have worked out our problems in relation to Vietnam; and if (Secretary of State Cyrus) Vance has some movement - date, structure, any kind of new thing - on the Middle East."

Young also accused Rhodesian Prime Minister Ian Smith of trying to lure Cuban and Soviet troops into neighboring Mozambique in an effort to get the United States involved. "The United States is determined not to fall into any trap involving U.S. troops in southern Africa," Young said.

Mozambique said that Rhodesian forces crossed into its territory two days ago and killed two civilians.

Young is scheduled to meet today with Tanzanian President Julius Nyerere, a key figure in southern African politics.