The Barry administration yesterday fired Patricia Quann, head of the District's Youth Services Administration, which has been under investigation by the FBI, the General Accounting Office and the U.S. attorney's office for nine months.

City Administrator Thomas Downs requested Quann's resignation late yesterday afternoon, according to sources.

Quann, who was appointed by Mayor Marion Barry to her post four years ago, had previously run a Maryland corrections center and served as a criminal justice assistant in Pennsylvania during governor Milton J. Shapp's administration.

Quann resigned for "personal, health and career reasons," according to a three-page statement issued by the mayor late yesterday.

In a memorandum to David Rivers, director of the Department of Human Services, which oversees the agency, Barry said, "I am deeply disappointed and have grave concerns about the problems of the Youth Services Administration . . . . I find it incredible that 99 YSA employes made more than 50 percent of their base salary in overtime last year. This indicates a serious lapse in management con- trols . . . ."

Robert Malson, a lawyer and aide to D.C. Social Services Commissioner Audrey Rowe, will serve as acting administrator.

Rowe, who also was Quann's boss, criticized press attention to the investigations of the agency and said Quann's dismissal was handled in an "uncivilized" fashion. Quann declined to comment.

Quann, Rowe and at least 14 other Youth Services employes testified recently before a federal grand jury examining the agency's management. Sources said Barry was displeased that he was not briefed on the Youth Services' subpoenas until a week after they were issued.

In recent months, federal investigators have set up shop down the hall from Quann's office. They are examining the nearly $15 million in contracts awarded by the agency to private firms in 1984 and 1985 -- the majority of which were issued without competitive bidding, according to sources.

Another aspect of the probe is alleged abuses of overtime that frequently tripled the salaries of a select number of counselors and administrators at D.C. youth facilities. The agency spent more than $6 million for overtime pay in 1982 through 1985, a rate that far exceeded other D.C. agencies.

A Department of Human Services study ordered by Barry found that 76 percent of all overtime paid by the department was to employes of the city's three youth facilities.

Investigators also are trying to determine whether city officials or staff members altered or withheld documents subpoenaed by a federal grand jury that began hearing testimony on the Youth Services case last month. According to sources, the FBI crime lab removed white correction fluid from time sheets in order to read employes' names that had been obliterated.

Barry said in his memo to Rivers that no employe in the future will be permitted to earn more than 20 hours of overtime per two-week pay period. He has requested Coopers & Lybrand, the city's private auditors, to examine all overtime records of Youth Services employes and their supervisors.

Barry said the records will be scrutinized "for any possible criminal activities." The mayor said he expects "each and every employe of District government to uphold the highest personal and professional standards. Those who abuse the public trust will be dealt with immediately and directly."

Barry said he plans to meet with D.C. Superior Court Judge Ricardo Urbina to seek ways to reduce the juvenile caseload, which has put a burden on the city's youth facilities.

E. Lawrence Barcella Jr., an assistant U.S. attorney in charge of the Youth Services probe, said yesterday he could not comment on Quann's forced resignation. "It would be inappropriate and premature to comment on the course or conduct of a grand jury investigation," Barcella said.

Anthony Salvimini, the evaluator in charge of the General Accounting Office's investigation of the agency, said he "cannot comment on it because it's an ongoing audit."

The youth agency is responsible for the District's three juvenile institutions, as well as an extensive network of privately run group homes.

Serious problems have plagued the facilities since the 1970s, when a District judge ordered improvements in the care and treatment of the detained youths. One of the facilities, the 38-bed Receiving Home, has experienced eight suicide attempts since January, according to staff reports of the incidents.

The agency's latest legal troubles began last fall, after congressional hearings examined whether the city violated federal laws concerning the special education of children being held in D.C. institutions. The hearings prompted the U.S. attorney's office to look into the agency's outside contracts.

The investigation has since broadened to include most of the agency's dealings with 80 outside contractors and alleged overtime abuses that cost the agency $50,000 every two weeks.

In addition to the federal probes, the agency also is facing a civil lawsuit, set for July, in which the Public Defender Service claims that children in D.C. youth facilities receive poor treatment and insufficient schooling and have been abused by staff members. The Public Defender Service defends many of the children living in the homes.

Charles Seigel, a spokesman for the D.C. Department of Human Services, which oversees Youth Services, said Quann "is someone who cared very much about the job and the children she was trying to help. It was a very difficult situation both within and without the administration."

Quann, in an interview earlier this year, said when she took over the agency, it was in serious financial shape, had excessive overtime and was understaffed.

"The system had kind of been floating. There had been acting administrators for some number of years," Quann said. She tried closing one facility, Cedar Knoll, to save money, but an increase in delinquent children under city care made this impossible.