President Bush urged Congress on Friday to postpone action for four months on $10 billion in loan guarantees for Israel, saying the debate could derail a Middle East peace conference. "Let's not blow it," Bush declared.

But Israel's ambassador, Zalman Shoval, made the formal request to Secretary of State James A. Baker III anyway."We have very serious economic problems," Shoval said. "And it's no secret we need that money quite urgently. It is a problem."

Bush indicated clear displeasure with Israeli Prime Minister Yit-zhak Shamir's determination to go ahead with the formal aid request anyway.

"We don't need an acrimonious debate just as we're about to get this peace conference convened," Bush told reporters.

Several important Democrats including Sen. Patrick Leahy, D-Vt., who heads a subcommittee that handles foreign aid appropriations, had signaled in advance their support for such a delay in the loan guarantees, intended to help Israel provide housing for an influx of Jews from the Soviet Union.

Sen. Claiborne Pell, D-R.I., chairman of the Senate Foreign Relations Committee, said Congress probably would agree to Bush's request for a delay,

Pell said he hadn't made up his mind. "I oppose settlements in the occupied territories, but Soviet Jews are not responsible for Israel's policy and should not be the ones to suffer for it," he said.

And Sen. Connie Mack, R-Fla., said in a letter to Leahy that "if Congress delays the provision of loan guarantees for Israel it would be perceived by the Arab world as a clear invitation to link U.S. humanitarian asssitance to Israel to concessions in the peace process. . . . The U.S.-Israel relationship must not become a bargaining chip in the peace process."

But Baker said the administration was not trying to hold "a club" over Israel's head or seeking a delay out of concern the Arabs might be opposed to the assistance.

"It's just that if this package is to move at this particular time I think that it would create conflict rather than avoid conflict," he said.