A U.S. District Court jury has convicted the maintenance director of the D.C. Department of Recreation, a chief mechanic and a third man of conspiracy and obstruction of justice in connection with a government investigation into possible misuse of recreational department funds.

The jury of eight women and four men, however, either acquitted the three men or was unable to reach a verdict on 17 other charges related to alleged misuse of $580 in department funds and alleged false statements made to a grand jury investigating the case.

The maintenance director, Howard F. Gasaway Sr., the mechanic, Julius L. Johnson Sr., and Herbert Lewis, a friend of Gasaway's daughter, each face a possible sentence of 10 years in prison and a $15,000 fine on the conspiracy and obstruction of justice convictions.

Testimony during a week-long trial before Judge John H. Pratt disclosed that the prosecution of the three men stemmed from an ongoing investigation into possible misuse of government funds, property and employes by recreation department officials. The investigation is being conducted jointly by the U.S. attorney's office here and the D.C. police department.

Now that the jury has returned its verdict, it is expected that Assistant U.S. Attorney Theodore Shmanda, who prosecuted the case, will subpoena Gasaway and Johnson to testify before the grand jury looking into those allegations.

Gasaway, 50, in tears as he left Pratt's courtroom yesterday, said that the government is using him as a "scapegoat" to obtain grand jury testimony against other department officials, Gasaway has been a department employe for 25 years.

"I've given more to this city than I've ever taken," Gasaway said yesterday in an interview.

The government contended that Gasaway, Johnson and Lewis conspired to hide from investigators the fact that a $238 transmission, purchased with recreation department funds, had been installed in Gasaway's 1974 Lincoln Continental. The government aruged that a second, cover-up transmission was turned over to police after an investigation began.

Johnson, 58, and Lewis, 36, also were charged in an indictment with making false statements to the grand jury about the transmission.

The grand jury accused Johnson, a recreation department employe for nine years, and Gasaway of using $342 in recreation department funds to purchase two sets of whitewall tires, at least one of which was installed on Gasaway's car.

The jury did not convict either Gasaway, Johnson or Lewis of any of the charges directly related to either the transmissions or the false statements, although those alleged acts were the basis for the conspiracy and obstruction charges. The jury also did not convict anyone of any of the charges related to the tires.

Gasaway has been on sick leave from the department since suffering a mild heart attack.Johnson has been working at the recreation department's transportation branch, a city hall spokesman said. Lewis, who lives in Arlington, is not a recreation department employe.

The jury announced late Friday that it had reached the two guilty verdicts involving all three men, and had acquitted Gasaway and Johnson of a charge that they used $186 in recreation department funds to purchase one set of the tires. Pratt directed the jury to return to the courthouse yesterday to continue deliberation on the remaining charges.

At 10:30 a.m. yesterday, Pratt received a note from the jury foreman that said one juror wanted to change her vote on the two guilty verdicts. An hour after Pratt ruled that no change could be made, the jury announced that it had acquitted Gasaway of one of the remaining charges involving the second set of tires and was unable to reach a decision on any of the remaining counts against the three men.

A source said yesterday that the juror wanted to change her Friday vote was the principal holdout for acquittal yesterday on the rest of the charges.

Attorneys for the three men indicated yesterday that they would file motions with Pratt contending that the jury's decision in the case were inconsistent and therefore should be set aside.