President Carter told a cheering audience at the Congressional Black Caucus dinner last night that Andrew Young would be ambassador to the United Nations "as long as I am president and he wants to stay here."

Carter lavished praise on the controversial former Georgia congressman and pledged to a crowd of several thousand that filled two hotel ballrooms that he was "determined" to have their top legislative priority, the Humphrey-Hawkins full-employment bill, "pass this year."

Carter's pledge on the jobs legislation - confirming a promise he made in the second of his two meetings with black caucus members last week - drew little applause.

But he [WORD ILLEGIBLE] the 4,000 diners at the Washington Hilton when he turned to foreign policy and praised the much-criticized Young as "a man's not afraid to speak out when he sees something wrong."

That brought the diners to their feet. And they were back up again, applauding, when Carter said: "I don't know of any one in the administration of Jimmy Carter who has donw more for our country throughout the world than Andy Yound.

"Even if you had'nt stood up for that," Carter added, "I was going to tell you that as long as I am president and Andy Young is willing to stay there, he'll be the United Nations ambassador."

Carter's praise of the former Atlanta congressman, whose free-wheeling comments have drawn frequent criticism inside and outside the administration, appeared to end whatever chill had developed from the criticism of his alleged lack of commitment to the Humphrey-Hawkins bill.

But Rep. John Conyers Jr. (D-Mich.), who stormed out of the White House last week in a disagreement with Carter over the issue, boycotted last night's dinner.

Rep. Parren J. Mitchell (D-Md.), black caucus chairman, announced that Conyers had told him he would attend no more public ceremonies until the full-employment bill was passed.

Sen. Edward M. Kennedy (D-Mass.), who spoke to the twin dinners in the Hilton and the Shoreham Americana a few minutes after Carter finished, had some political sport with the Carter-Conyers disagreement.

He said he sympathized with Conyers' appeal for a "Camp David summit" to speed passage of the bill. "I've been trying to get there for years myself," Kennedy said.

Kennedy made another teasing reference to his rumored status as a 1980 challenger to Carter's renomination. "I have my differences with President Carter," he said, "but I didn't think they'd put us in different hotels."

More seriously, Kennedy trumped Carter's pledge to break the Senate deadlock on approval of the House-passed full-employment bill by suggesting that it would be done by "attaching is to the tax-reduction bill on the Senate floor."

White House officials expressed skepticism that such a tactic would work.

Both Kennedy and Carter promised to press ahead on social legislation aimed at reducing unemployment and improving urban life. But Carter, as he has been doing in all his recent speeches, gave almost equal emphasis to the battle against inflation.

But the crowd seemed less interested in Carter's program than in the symbolism of his praise for Young and other black appointees in his administration.

At the end of his speech, Carter called up from the audience Rosa Parks, the black whose refusal to give up her seat on a bus launched the 1955 Montgomery, Ala., bus boycott. The president embraced her and once again, the hall was filled with cheers.

By the time Carter left the Hilton with a final shouted "Right on!" to the crowd, the tensions that preceded the dinner seemed forgotten.

Earlier last week, Carter, Vice President Mondale and caucus members got into a heated dispute over the administration's handling of the so-called full-employment legislation during a White House meeting. Conyers walked out in anger and rumors started that the president would be "disinvited" to address the dinner last night.

But the dispute appeared to be resolved Thursday when Carter and Mondale again met with acucus members, including Conyers, in a White House political makeup session. Mitchell said the president promised to put passage of Humphrey-Hawkins during the current legislative session on his "must" list. The legislation is named for its cosponsors, the late senator Hubert H. Humphrey (D-Minn.) and Rep. Augustus F. Hawkins (D-Calif.).

Mitchell also said Carter promised to push the bill as designed to help all Americans. He said he and his colleagues believed the measure was languishing on the Senate calendar because it was perceived as "just another bill to help blacks."

The bill would establish as a national goal reducing the overall unemployment rate to 4 percent by 1983. The administration began supporting the measure after it was watered down from an earlier version.

Mitchell was asked yesterday if he thought that the caucus and the administration were expending too much political energy to secure passage of the weakened bill, which contains no funding levels or concrete steps for implementation.

"No," he said. "Anyone can try to pick the bill to pieces. If the bill is so meaningless, then I'd like to know why powerful organization like the United States Chamber of Commerce are applying so much pressure to try to stop it."

For his part, Carter repeated his contention that the administration has always regarded passage of Humphrey-Hawkins as a top-priority item.

He said his administration has been working with the caucus and the Full Employment Council headed by Coretta Scott King, widow of civil rights leader Martin Luther King Jr., "to ensure passage this year of this long overdue and much needed legislation."