President Carter met yesterday with envoys of Syria and Jordan as the recurring problem of Palestinian participation in Arab-Israeli peace talks impeded attempts to launch a Geneva conference.

At the United Nations, Egyptian Foreign Minister Ismail Fahmi also singled out the Palestinian issue as the prime obstacle for resuming talks in Geneva.

Fahmi insisted that the Palestine Liberation Organization must participate "on the same level" as Egypt, Syria and Jordan in a unified Arab delegation that would negotiate with Israel. Syria's foreign minister, Abdel Halim Khaddam, expressed a similar position after his talks with Carter.

But Jordan's special envoy, Abdul Hamid Sharaf, whose nation clashed fiercely with the PLO in 1970, spoke only of "Palestinian" participation in a unified Arab delegation at Geneva, following his meeting with Carter. The Palestinians, Sharaf said, "should choose their own representative."

Israel refuses to negotiate with the PLO on grounds that the organization is pledged to destroy Israel. The United States has a commitment to Israel that it will not deal with the PLO unless the group acknowledges Israel's right to exist. At the same time, the United States is leaning on Israel to be "flexible" about PLO participation in a pan-Arab delegation, which is intended to circumvent the PLO controversy.

A flurry of excitement developed after the Carter-Khaddam talks when the Syrian envoy, speaking in Arabic, told reporters that ". . . I insisted on our position, which is that all the parties concerned have to participate and that's why the PLO has to be involveed, and our two viewpoints coincided regarding the possibility of forming a unified Arab delegation including the PLO."

If correct, that would be a significant departure in the official U.S. position on the PLO. PUblicly, the United States has said only the "Palestinians" should be at Geneva.

White House spokesmen refused to say outright if the Khaddam description of the Carter position was accurate or not. But then they backed away from it, saying: "Our views coincide on the desirability for a unified Arab delegation. But obviously the details are still under discussion."

Khaddam also said there must be Israel withdrawal from all Arab territory it occupied in the 1967 Arab-Israeli war, an independent Palestinian state, and the right of Palestinians to return "to their land."

A White House statement acknowledged that "differences exist" between U.S. and Syrian positions. "Differences" previously were acknowledged only after Carter's talks last week with israeli Foreign Minister Moshe Dayne. The term did not appear in White House statement s on talks with either the Egyptians or the Jordanians.

The Syrian and Jordanian envoys yesterday praised Carter for his mediator efforts, and expressed belief that a Geneva conference will be held this year. Spokesman Jerrold Schecter said. "We fell that progress has been made" in the two weeks of White House talks, with Secretary of State Cyrus R. Vance will continue at the United Nation in New York.

At the United Nation, Egypt's Fahmi accused Israel of pushing the Middle East toward "an explosion." Israeli U.N. representative Chaim Herzog countercharged that this was "a flagrant violation of the 1975 Israeli-Egyptian agreement to de-escalate political warfare.