Outgoing D.C. City Council member Willie J. Hardy (D-Ward 7) yesterday formally endorsed congressional aide Johnny Barnes in his bid against two other Democratic challengers for Hardy's council seat this fall.

Barnes, legislative assistant to D.C. Del. Walter E. Fauntroy, is a relative newcomer to Ward 7 electoral Politics.

He faces stiff opposition in the Democratic primary from city realtor H. R. Crawford and D.C. School Board employe Emily Y. Washington, both of whom are proven vote-getters in previous campaigns. John West is running unopposed in the Republican primary for the Ward 7 seat in the eastern fringe of the city.

Barnes, according to observers, hopes Hardy's endorsement will compensate for his lack of name recognition and provide him a built-in organization and a core of supporters from the poorer precincts of the ward north of Fort Dupont Park -- Hardy's stronghold.

Barnes, Crawford and Washington are all residents of the world's "Silver Coast," an enclave of middle-to-upper class professionals south of the park.

Barnes, a 32-year-old attorney, called Hardy's endorsement yesterday "very important and vital to my efforts."

Hardy announced last week that she was leaving the council at the end of her term to open a private consulting firm. Yesterday, she said she was endorsing Barnes because "we need someone who's not tied to any special interest groups."

She would not say whether she was refferring to Crawford or Washington as tied to special interests.