Financially troubled real estate investor Conrad Cafritz has sold much of his interest in Washington Harbour, the Georgetown riverfront development that had been the brightest symbol of his success.

Cafritz's Japanese investors in the Washington Harbour venture have chosen someone else to head their partnership and are interviewing candidates to assume Cafritz's role as manager of the office and retail complex, in charge of leasing, maintenance and other day-to-day functions.

The 51-year-old developer stunned the Washington business establishment two months ago by disclosing that he was running short of cash and was asking his bankers for more time to repay his loans.

Cafritz is son of the late Morris Cafritz, who was one of the Washington area's more prolific developers. Once the image of financial strength, Cafritz has become a symbol of the problems that developers and lenders are facing now throughout the metropolitan area and nationwide.

Cafritz said yesterday that he sold his interest in Washington Harbour at a profit -- he declined to say how much -- adding that he had no regrets about the deal. He will serve as a paid consultant on the project for three years.

"In our situation, raising cash is important for us," he said. Cafritz added that he has almost concluded the sale of several other properties, which he declined to identify.

The acquisition of Washington Harbour in December 1988 -- reportedly for more than $200 million -- had been a personal and professional triumph. It linked the Cafritz name to one of the area's landmark properties, and it removed Cafritz's longtime rival, Western Development Corp. Chairman Herbert S. Miller, from the ownership of a project Miller had labored years to develop.

The Japanese investors who backed Cafritz's takeover of Washington Harbour and own most of it may name a new manager of the property within three weeks, according to John Spuches, a New York lawyer who represents them.

"They wanted a property manager or management group that was going to give undivided attention to this particular project," Spuches said. The investors are considering about a dozen candidates for the job, including local real estate firms Smithy Braedon and Carey Winston Co., sources said.

The identities of the investors and the new head of their partnership could not be determined. Long-Term Credit Bank of Japan Ltd. helped finance the investors' purchase of Washington Harbour.

Cafritz yesterday said his company had accomplished "a very good piece of work in turning the project around." Cafritz leased a large area of office space and signed the Ark Restaurant Corp. to open a restaurant in the space left vacant when Potomac restaurant failed in 1987. The new restaurant, called Sequoia, is scheduled to open next week.