Billy Carter's recollection of events surrounding his dealings with Libya conflicts on several key points with evidence, presented to a Senate subcommittee by Justice Department and White House officials.

The subcommittee investigating Billy Carter's affairs released yesterday a memorandum by Joel Lisker, chief of Justice's Foreign Agent Registration Unit, which quoted Carter characterizing a $20,000 payment from the Libyans as "partial reimbursement for his expenses in hosting a reception for the Libyan delegation in January of 1979" in Georgia.

According to the June 11 memo, which recounted a meeting with Carter the same day, the president's brother told Lisker that he had incurred $40,000 worth of expenses hosting the Libyans in Georgia.

Carter testified yesterday, however, that the $20,000 was an advance on a $500,000 loan he had requested from the Libyan government. He could not explain why the $20,000 check, unlike a later check for $200,000 he received from the Libyans, did not have the word "loan" written on it.

In another document released yesterday, FBI agent Richard E. Fugatt said Carter told him in a Jan. 16 interview that his expenses from the Libyans' Georgia trip were between $6,000 and $7,000.

When Lisker questioned Carter in June as to why his payment had been $20,000 for expenses he had estimated at $6,000 to $7,000, Carter said the earlier estimate was incorrect.

In this second day of testimony, Carter was sharply questioned by senators about the loan and other apparent inconsistencies. The senators said that while no major revelations of illegal behavior have come out so far, Carter's testimony raised new questions to be explored in the investigation. For example:

Carter testified yesterday that he did not inform a financial consultant who was negotiating with the Libyans for the $500,000 loan that he had already received $220,000. Carter said he hoped to receive the full $500,000 from the Libyans and then use it to immediately pay back the $220,000.

Fugatt's FBI report quotes Carter as saying that Frank Terpil, a gun runner, contacted him in Americus, Ga., after his trips to Libya regarding "the sale of a large number of machine guns to Libya, but that nothing came of it." Carter said yesterday he did not recall telling Fugatt that, adding that he had never spoken to Terpil in Americus.

Carter insisted yesterday that he had not spoken to any administration official before his first trip to Libya in late September 1978. However, in a memo to the subcommittee, William B. Quandt, formerly with the National Security Council, said he had cautioned Henry (Randy) Coleman, Carter's close associate against that trip.

During one telephone conversation, Carter came on the line and said "he did not need to have people in Washington telling him how to conduct his private affairs," Quandt recalled.

Carter testified for seven hours yesterday. Sen. Strom Thurmond of South Carolina, ranking Republican on the subcommittee, told the president's brother. "You have presented your case well, but I am skeptical on a number of points. I believe this investigation will have to probe deeper."

One question Thurmond said he wanted to explore was whether Carter earned $600,000 from public appearance after his brother became president. Carter's attorney, Henry Ruth, said Carter has given his tax returns to the subcommittee, but doesn't want to reveal them publicly. "The question is whether Billy Carter retains any shred of privacy at all," Ruth said.

Several senators said they felt Carter, who answered questions tersely and volunteered no information, was less than forthcoming. "Billy Carter has been well coached," said Sen. Max Baucus (D-Mont.) "But we have the uneasy feeling his answers are not directly on target. There's a lot he's not saying."

However, Baucus added, "We are unable to point out the holes because there has not been enough time to take depositions from enough other people to have a sufficiently complete picture. We really don't have adequate preparation to get to the bottom of these questions."

Baucus' worries apparently registered with other members. Late yesterday afternoon, subcommittee chairman Birch Bayh (D-Ind.), who has been anxious to finish the investigation well before the election, postponed next week's hearings to give the subcommittee more time to prepare. Justice and State Department witnesses are now scheduled to testify in two weeks.

Carter testified yesterday that he was to receive 51 percent of the commissions to be made from arranging the purchase of 100,000 barrels of Libyan oil a day for Florida-based Charter Oil Co. Coleman was to receive "a substantial amount" also, he said, and another friend, Arthur Cheokas, would get part of the money.

Carter denied, however, that he had ever discussed sharing the oil commissions with George Belluomini, a California farmer and furniture importer. On Wednesday, Ronald Sprague, a financial consultant, testified that client Belluomini had paid his way to Libya to help Billy Carter negotiate the loan and the oil deal. Sprague said he and Belluomini expected to share the commission.

Thurmond questioned Carter about a Justice Department report that Belluomini and Sprague are being investigated for drug smuggling. The the report was released suddenly by the subcommittee yesterday after several news reporters had inquired about it.

Bayh called it irrelevant to the investigation. Nonetheless, Thurmond asked whether "it's possible [Belluomini] was playing up to the presidents' brother for the purpose of feeling some security if he ever got caught in the drug business."

While Ruth reminded Thurmond that there were no charges against Belluomini, Carter replied that it "could be possible that everyone I met in 1977" was using him, but he doubted it. "It's extra dangerous for anyone to be friends with me," he said. "They seem to get investigated for being friends with me."

Carter has estimated that since his brother became president he has spent 500 eight-hour days defending himself in 10 investigations, including several by the Internal Revenue Service and the Justice Department in connection with the Carter warehouse business.

In a financial statement released yesterday, the subcommittee revealed that Carter's expenses now exceed his income by $5,600 a month.He owns $920,000 in assets, mostly real estate.