Lyn Nofziger, a longtime friend and aide to President Reagan, was found guilty yesterday of illegal lobbying at the White House in 1982 for the Wedtech Corp. and two other clients that had hired him as a Washington consultant.

A U.S. District Court jury convicted Nofziger on three counts of violating the 1978 Ethics in Government Act but returned a not-guilty verdict on a fourth count, the only one that had been lodged against both Nofziger and his partner, Mark Bragg.

U.S. District Court Judge Thomas A. Flannery told Bragg he was free to go and said he would sentence Nofziger on March 25. He faces a maximum penalty of two years in prison and a $10,000 fine on each count, but lawyers familiar with the case said they would be surprised if he draws any prison time.

The plain-spoken Nofziger, 63, who first worked for Reagan in California and followed him to Washington as White House political director, said he would fight the verdicts in any event and predicted eventual "vindication."

"It's a lousy law," he said of the conflict-of-interest statute under which he was tried. "It doesn't apply to the Congress. It doesn't apply to the judiciary. It doesn't apply to those below a certain salary level . . . . It's like running a stop sign."

Independent Counsel James C. McKay, who directed the prosecution, seemed as unhappy as Nofziger was unrepentant. McKay said he found the outcome "depressing." Asked why, he said, "Well, I just hate to see someone get convicted of a felony. It's just tough. But we felt we had to do our job."

It was the second jury trial conducted under the independent counsel law that Congress enacted after the Watergate scandal and the second conviction in less than two months. Former White House deputy chief of staff Michael K. Deaver was convicted Dec. 16 of lying to a congressional subcommittee and to a federal grand jury about his contacts as a lobbyist after leaving the White House.

Other prominent Reagan administration figures are still under investigation. McKay is scrutinizing Attorney General Edwin Meese III's conduct in the Wedtech scandal and other matters. Independent Counsel Lawrence E. Walsh is apparently preparing to secure indictments in the Iran-contra affair.

Nofziger was found guilty of attempting to influence then-presidential counselor Meese in April 1982 on behalf of the now-bankrupt Wedtech Corp., of trying to influence then-White House aide James Jenkins in August 1982 for the Marine Engineers Beneficial Association (MEBA) and of improperly lobbying two National Security Council staffers in September 1982 for the Fairchild Republic Corp., makers of the A10 antitank aircraft.

The 1978 ethics law prohibits former senior government officials from lobbying at their old agencies for a year after leaving on any "particular matter" that is of "direct and substantial interest" to the agency where they worked. Nofziger left his job as assistant to the president for political affairs on Jan. 22, 1982.

Despite complaints that the untested law is, as Flannery said during the trial, "hardly a model of clarity," members of the jury of eight men and four women said they had no trouble or hesitation in applying it. Some said they thought the one-year rule is a good one.

"For any administration, it's wrong, within a year, to show your influence," said juror Herbert E. Robinson, a Postal Service clerk.

Foreman Towana L. Braxton, a mail clerk at the U.S. International Trade Commission, said of the verdicts: "I think the message it sends is you can be prosecuted for not obeying the law. We are taught that the laws are to be obeyed."

Ironically, the count on which Nofziger and Bragg were found not guilty was the allegation that triggered McKay's investigation and ultimately their indictment. This charge rested on a May 28, 1982 letter that Nofziger allegedly signed and sent to White House aide Jenkins at Bragg's behest.

The letter, signed "Lyn" asked Jenkins for help in securing a letter of intent from the Army that Wedtech could use in getting supplemental financing for the long-sought Army engine contract. But an FBI handwriting analysis was inconclusive and defense attorneys denied that Nofziger had signed it.

Nofziger's and Bragg's lawyers also contended that the letter was supposed to have been sent to the Army, which would not have been illegal, and that it was actually signed by another Wedtech lobbyist, Stephen Denlinger, and delivered to the White House without Nofziger's approval.

Members of the jury, which deliberated for more than six hours since Wednesday, said they reviewed the evidence, count by count, and easily reached unanimous verdicts on all charges but this one.

"The fact that {Nofziger's and Bragg's} secretaries denied knowing anything about that letter and that Mr. Denlinger did not know . . . who typed it or even who gave it to him -- it was just too much," said juror Leslie J. Charles, a speech-language pathologist for the D.C. schools. "We couldn't decide beyond a shadow of a doubt."

Nofziger's difficulties began last year when federal and state authorities in New York began investigating the Bronx-based Wedtech's payments of cash and stock to politically connected consultants and law firms and, in the process, came across the May 28, 1982 letter.

That led to McKay's appointment by a special three-judge federal court panel last February. He uncovered the evidence behind the other charges, beginning with an April 8, 1982 note Nofziger sent to Meese, warning him that "it would be a blunder" not to award the engine contract to Wedtech despite the Army's reluctance. Nofziger reminded Meese in that note of President Reagan's 1980 campaign commitment to revitalize the south Bronx.

Meese, who was called as a prosecution witness, said he couldn't remember getting the note or doing anything about it. Jurors indicated they didn't pay much attention to his testimony as a result.

Wedtech received the no-bid $32 million Army engine contract following a May 19, 1982 White House meeting that Jenkins convened as Meese's top deputy and that prosecution witnesses said broke the impasse.

The count involving the marine engineers union rested on an Aug. 20, 1982 note Nofziger sent to Jenkins on the subject of using more civilian crews on noncombat ships, an issue that the union had hired Nofziger and Bragg to promote for $100,000 a year. Reagan had endorsed the idea at an Aug. 4, 1982 Cabinet Council meeting, but Nofziger complained nothing was being done about it.

In the note, Nofziger reminded Jenkins that MEBA President Jesse Calhoon had "been supportive of all the president's endeavors," including a controversial tax increase that had just passed the House. "Why not help our friends?" Nofziger asked.

Perhaps the strongest count involved Nofziger's lobbying for continued production of Fairchild-Republic's imperiled A10 aircraft. According to a note Meese kept, the A10 was the first item on the agenda of a Sept. 8, 1982 meeting with President Reagan and other top aides.

Nofziger was hired by Fairchild for an initial $25,000 paid to him on Sept. 23. Two NSC officials testified that Nofziger told them at a Sept. 24 meeting how President Reagan's "political word on the Hill" might be debased if the A10 weren't kept alive.

That was an allusion to an extraordinary directive Reagan had signed on Aug. 20, 1982, instructing the secretary of defense to try to find ways to continue A10 production.

The jurors filed into Flannery's courtroom to announce their verdicts at 10:55 a.m. Nofziger, wearing his favorite Mickey Mouse tie, took the findings stoically while his wife, Bonnie, and two married daughers, Susan Piland and Glenda Tarry, sat in a front row, struggling to keep their composure.

When the single "not guilty" verdict was announced for him and Bragg, Nofziger leaned toward Bragg with a gesture of congratulations. He left the courtroom, saying it was just "Round One."

Outside, before a bank of microphones, Nofziger was asked if he felt an injustice had been done to him.

"Certainly I do," he said. "I seem to have been found guilty of getting this administration to do what it promised to do."