While Mayor Walter E. Washington sat and listened, members of a House subcommittee bid a touching and laudatory farewell to him yesterday and then gave the outgoing mayor what he wanted most from them - approval of the city's revised plan for the proposed Washington Civic Center.

Having helped control many a District of Columbia government budget over the years, the House District Appropriations subcommittee, particularly its chairman, Rep. William H. Natcher (D-Ky.), was effusive in its praise for the mayor and his 11 years of service as the city's chief executive.

"I have served on this subcommittee for 24 years, and I want to commend you for a job well done," Natcher said.

"You served during a time when almost anyone would have tailed . . . But you did not fail and the city is in better shape than in any time I've been here," he said.

A powerful subcommittee chairman who single-handedly blocked the mayor's pet convention center proposal five years ago and who was not an early or enthusiastic advocate of home rule, Natcher made a veiled reference to Washington's recent primary election defeat and told him he would always be well regarded here.

"History will record the fact that you've been a good mayor," Natcher said, "and as we go into the future the people will appreciate you more."

Washington, who oficially conceded his election loss yesterday and promised to support primary winner Marion Barry in November, was clearly moved by the praise and later thanked subcommittee members for their compliments.

The occasion for this informal testimonial was the mayor's appearance before the subcommittee for a crucial public hearing on the city's revised proposal to build a $99 million convention center near Mount Vernon Square. At Natcher's not unexpected urging, all but one of the five subcommittee members in the attendance backed the new plan.

The revised proposal, scaled down in size and cost from an earlier plan that encountered much congressional opposition, is expected to receive careful scrutiny next month by the more skeptical Senate District Appropriations subcommittee, which must also approve the project before funds can be spent on construction.

Its chairman, Sen. Patrick Learhy (D-Vt.), engineered a compromise agreement in May that would allow the center to proceed once the city showed it would not be a burden of D.C. taxpayers.

A key element in the agreement requires that there are much commitments of private "spin-off" development from the center to provide tax revenues equal to the facility's annual loan repayment and operating costs.

Leahy, who has announced he will hold hearings on the revised plan Oct. 10 and 12, has criticized the city's list of likely spin-off projects as being insufficient. Natcher's committee yesterday did not raise the subject.

Representatives of the city's hotel, tourist, labor and business sectors continued to argue enthusiastically for the controversial project, saying a convention center is vital to the District's economic well-being.

Robert Linowes, president of the Metropolitan Washington Board of Trade, told Natcher's subcommittee the city "has made a sincere and successful effort" to meet the conditions necessary to win approval for building the center.

"At stake," Linowes said, "are 4,000 new jobs in the retail and service industry . . . relief for city taxpayers through new sources of revenue . . . and change in the social and physical environment" of the city's old downtown area.

But Harriet Hubbard of the Dupont Circle Citizens Association made an impassioned plea to Natcher to allow District residents to approve or disapprove the center in a referendum.

"Please Mr. Natcher, it's really not fair. Let us decide how we want to spend this money," said Hubbard, who complained that most of those supporting what she called "this lameduck project," including Linowes, do not live in the city.

With Washington sitting at the table with her, Hubbard said the mayor had been undeservedly praised, was inaccessible to citizens and had shaken the public's faith in government because of his administration's "proclivity for taking the advice of people who don't live here."

Rep. Clair Burgener (R-Calif.), noting the city council's unanimous support for the center, said he hoped Congress could eventually "cut the apron strings" and give the District "true home rule." But Rep. Gunn McKay (D-Utah) voiced a lone subcommittee objection to the project, warning that the city's estimates for its success were faulty and that "we have not seen the last on this project."