Nearly a year after first considering the nomination, the Senate Rules Committee voted 7 to 2 yesterday to recommend that John McGarry be confirmed for a Democratic seat on the Federal Election Commission.

But Republican senators said they still had misgivings about McGarry's background and explanations of his tax returns and House financial disclosure statements. They predicted the nomination would run into opposition when it reaches the Senate floor sometime after Labor Day.

"I'm not satisfied yet," Sen. Robert Griffin (R-Mich.) said. "We had too much trouble getting answers from Mr. McGarry."

Griffin voted against McGarry, as did Sen. Howard H. Baker Jr. (R-Tenn.), who voted by proxy.

Without speaking directly of McGarry, Griffin also said, "I'm very disappointed, frankly, in the quality of some of the nominees advanced before this committee."

Sen. Mark O. Hatfield (R-Ore.), who had led questioning of McGarry, voted to recommend confirmation, but later said he still had "grave reservations" about the qualifications of McGarry, who is special counsel to the House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass).

Hatfield said that while extensive investigation into McGarry's finances produced "no smoking gun," there were enough questions raised to require extensive debate in the Senate.

McGarry, contacted in Boston where he is undergoing treatment for a neck injury, said he was "delighted at the bipartisan support" he received. He added that he would try to answer any further questions that might be raised about his finances when the nomination is taken up by the Senate.

Sen. Dick Clark (DIowa), voted for confirm*ation, but noted he could change his mind when a vote is taken by the full Senate. Clark said he wanted time to study more carefully a report prepared by Reka Hoff, a General Accounting Office tax expert assisting the committee, which was given to the members only shortly before the vote was taken.

Committee Chairman Claiborne Pell (D-R.I.), Sen.Howard W. Cannon (D-Nev.), Sen. Harrison A. Williams Jr. (D-N.J.) and Sen. Wendell H. Ford (D-Ky.) voted for McGarry, as did Sen. Robert C. Byrd (D-W. Va.), who voted be proxy.

Cannon gave the strongest support for McGarry, saying, "I believe that all questions or inferences of improper or illegal actions on the part of Mr. McGarry in the handling of his financial affairs have been fully examined and resolved in Mr. McGarry's favor."

The committee did not discuss Hoff's final report before voting, even though she concluded that McGarry's tax returns contained several improper deductions and miscalculations during 1973-1976.

After studying audit reports from the Internal Revenue Service, Hoff still contended that she was correct in her earlier statements that McGarry improperly deducted $26,000 in commuting expenses and improperly calculated depreciation on a computer leasing arrangement.

She also maintained that McGarry miscalculated his self-employment taxes.

The IRS checked McGarry's returns for each of the years in question, however, and the committee apparently agreed with Cannon, who said, "I see no reason why this committee should assume the role of a tax court to review the judgment of the IRS or to mediate the disagreements the GAO tax consultant has with the IRS and Mr. McGarry's ax advisers."

Hoff's report will be forwarded to the Senate along with the committee's recommendation. McGarry will also be given a chance to reply to Hoff's final conclusions.