The sprawling, 20-acre estate of businessman Morton Lebowitz in wooded suburban McLean may have seemed an unlikely place to hold a forum for candidates running for major of the District of Columbia.

At one point in fact, a somewhat perplexed Ivanhoe Donaldson, who is managing the mayoral campaign of City Council member Marion Barry, told a bystander that he candidate probably should not have come. "Would the governor of California go to a forum on California politics in Idaho?" Donaldson asked.

Still, seven candidates for the city's top elected position went to McLean yesterday, fanned away bugs, ate boxed chicken dinners and made political pitches in shrub and tree-shaded garden to about 75 people sitting on white folding chairs.

The occasion was the annual membership meeting of the Voice of Informed Community Expression (VOICE) (VOICE), an influential, 132-member biracial group of Washington area business and civic leaders established more than a decade ago as a self-proclaimed "silent majority" voice during a time of outspoken and often militant black nationalist activism.

Five candidates running for the Democratic mayoral nomination in the Sept. 12 primary were on hand - Mayor Walter E. Washington, John Ray, City Council Chairman Sterling Tucker, Dorothy Maultsby and Barry, Republican candidate Jackson R. Championa and Susan Pennington, candidate of U.S. Labor Party, also attended.

For some of the candidates, it was a chance to remind the audience of old friendships. Washington, whose political supporters were dominant in the group, told the audience that talking to yourself."

Tucker, former executive director of the Washington Urban League, said he had written part of one of his books by the side of the swimming pool on the Lebowits estate, where VOICE meets annually, Pennington, who used to work with the now-defunct Health and Welfare Council of the National Capital Area, said the VOICE membership list was similar to a roster of HWC supporters.

Even Barry, who had been one of the militant voices of city activism at the time the organization was formed, said he found common ground "One thing we have in common with Virgina is airplane noise," he told the group.

VOICE will make no formal endorsement nor financially contribute as a group to any of the campaigns. But its members hold prestigious positions in business, civic and community groups in the city and could play key roles in determining who wins the election.

At the forum yesterday, Barry accused his two major rivals - Washington and Tucker - of overlooking the problems of poor, unemployed and neglected people in the city and failing to stress improvement of public education as an issue in the campaign.

He noted how both Washington and Tucker had emphasized in their speeches to the group that conditions in the city had improved in the past 10 years.

"If you examine the facts, however," Barry said, "the 40,000 families out of 180,000 whose rent are more than 30 percent of their incomes will not agree with the mayor and Sterling." Nor, he said, would the unemployed, persons who live in dilapidated housing and those who have seen few city improvements along the riot-torn II Street corridor in Northeast Washington.

Washington, who had left by the time Barry spoke, repeating what has been a theme in his campaign, said that during his 11 yars as mayor, the city has been rebuilt and is now "on the top." There are still some problems, including unemployment among black youth, he said.

Tucker said many of his efforts to improve the city had been thwarted by Washington's administration which had failed to install effectively and efficiently some of the programs enacted by the City Council.

"No one can say that Walter Washington has not done well and for all that we are grateful," Tucker said. "But 11 years is too long (for one mayor)."

Both Ray and Maultsby told the group that only they as non-members could bring real change for "true new leadership" as Ray termed it.

Pennington said she is opposed to a commuter tax and against a requirement that city employes live in the District. In a presentation laden with economic policy discussion, she said her candidacy was aimed at bringing the city "back into a pro-growth perspective."

Champion said the city must attract light industry, provide more technical skills traming for young persons and immediately enact legislation legalizing a city-run lottery.