President Carter welcomed Bishop Abel Muzorewa, the unrecognized and embattle prime minister of Zimbabwe-Rhodesia, to the secluded retreat at Camp David yesterday for a meeting that both leaders hope will open the way for an end to the breakaway British colony's guerrilla war.

But reports coming out of the 30-minute meeting suggested that the two leaders had continued their sharp disagreement over the path to be taken to that end, with Carter pressing for significant broadening of Muzorewa's black majority support as the condition for a change in attitude by Washington.

Muzorewa, however, argued that he had already established perhaps the most democratic government in Africa, and asked Carter to recognize this by ending economic sanctions against the biracial Salisbury administration, informed sources said.

Muzorewa gave no indication in the meeting that he was prepared to make significant changes at home, they reported.

Despite the disagreements, Muzorewa emerged from the meeting saying that he was "tremendoulsy encouraged" by his reception by the president, which both Muzorewa's supporters and critics said had conveyed a new legitimacy to his authority.

Administration officials suggested that in return the president feels he has brought some time on congressional efforts to lift economic sanctions. The meeting was arranged by Sen. Jesse A. Helms (R-N.C.), who has led Senate action on that issue. Helms indicated yesterday that he would give Carter time to consider his meeting with Muzorewa before taking any new step.

Muzorewa is to fly to London today for meetings Friday with Prime Minister Margaret Thatcher and Foreign Secretary Lord Carrington. Public statements by the White House and Muzorewa yesterday indicated that the London meetings could be crucial to Muzorewa's drive to get an immediate lifting of sanctions as a way to restore stability and end the war.

"I think I can summarize my meeting by saying that I've been tremendously encouraged," Muzorewa told reporters after returning from Camp David by helicopter, "but I cannot go further because I have another meeting in about 48 hours with another party involved, the British government."

A three-paragraph satement issued by the White House put new emphasis on the administration's alignment of its policy with the Thatcher government, which has made clear its intention to seek an end to sanctions by November at the latest.

Signs emerged yesterday of careful coordination between Washington and London on the handling of Muzorewa's trip. Carter and Thatcher appear to be pressing Muzorewa to demonstrate clearly that he has in fact taken power from Zimbabwe-Rhodesia's 4 percent white minority population before internal pressures result in an end to U.S. and British sanctions.

Carter was described by the White House statement as having "expressed the hope that the Muzorewa administration would work closely with the United Kingdom in seeking non-military, political means to further the goal" of "independence based on full political participation and human rights guarantees for all its citizens."

The White House satement did not mention sanctions. A White House source would say only that the president had told Muzorewa that "it would not be helpful to lift sanctions at this time."

Carter and the U.S.-educated Methodist clergyman were alone for most of their meeting. White House and State Department spokesman said Vance participated, but they did not say for how long, Helms, in arranging the meeting, had suggested that the two leaders "sit down alone in quiet and get to know each other, free of the presence of others who might well create an implicit adversary atmosphere."

Helms in the past has sharply criticized Vance and his principal aides for opposing Muzorewa and allegedly supporting the Patriotic Front guerrilla forces, led by Joshua Nkomo and Rogert Mugabe.

Muzorewa publicly attacked Andrew Young, the U.S. ambassador to the United Nations, on Tuesday for allegedly turning Carter against him. Young, frequently identified as the main architect of administration Rhodesia policy, was in Rome yesterday for a speech to the Food and Agriculture Organization (FAO) while Carter was meeting Muzorewa.

Despite Muzorewa's failure to win specific support from Carter, the meeting was seen as a boost for Muzorewa both by African diplomats who opposed it and by congressional supporters of Muzorewa.

"My initial reaction is that things seem to be sllipping," Nigerian Ambassador Olujimi Jolaoso said in response to a reporter's question. "Seeing the president adds a compleltely different color to the picture than Muzorewa seeing Secretary Vance. You have the work of recognition without the name I would be very glad to be proved wrong, but it is, after all, recognition that Muzorewa wants."

Rep. Robert E. Bauman (R-Md.) who dined with Muzorewa Tuesday night, said the meeting "was not a formal recognition, but it does constitute the head of one state meeting another. The bishop was encouraged by the hearing he got from Vance, and I am sure the meeting with the president was useful."

State Department officials said Carter had never before met with someone who claimed to be the leader of a government that the United States has refused to recognize.

In another development, the House reaffirmed its position that the decision on lifting sanctions should be left to Carter.

It rejected, 248 to 168, a resolution that would have supported a Senate provision that would require Carter to lift sanctions immediately. CAPTION: Picture, Prime Minister Muzorewa and former secretary of state Henry A. Kissinger meet briefly last night. AP