Mayor Marion Barry and all but three members of the D.C. City Council yesterday endorsed Democrat John Ray's candidacy in the May 1 special election to choose a successor to Barry as an at-large council member.

Democrat Ray is running against 11 other candidates for the chance to complete the remaining 18 months of Barry's four-year term. Since January, he has served as Barry's interim replacement on the Council by appointment of the D.C. democratic State Committee.

Six Council Democrats joined Barry in endorsing Ray yesterday: Betty Ann Kane (at large), David A. Clarke (ward 1), John A. Wilson (ward 2), Polly Shackleton (ward 3), William R. Spaulding (ward 5) and Nadine P. Winter (ward 6).

Ray also was endorsed by the Council's two other at-large members-Republican Jerry A. Moore Jr. and Hilda Mason of the D.C. Statehood Party.

The three council members not endorsing his candidacy were Chairman Arrington Dixon, Willie J. Hardie (D-ward 7) and Wilhelmina J. Rolard (D-ward 8).

Barry said Ray, a lawyer, was "more than qualified" for the post. "John Ray has the ability," Barry said, "to remain true to his principles while at the same time finding ways to be cooperative and respectful of other points of view held by his colleagues."

Other candidates in the at-large race are manpower specialist Richard Blanks, neighborhood worker H. Chris Brown, Curtis Butler, former republican Jackson R. Champion, neighborhood worker Lin Covington, Francis Goldman, office administrator David A. Hemphill Sr., former Council member Douglas E. Moore, planner Hector Rodriguez and U.S. Labor Party organizer Stuart Rosenblatt.

Voters in the May 1 election also will choose a new at-large member of the school board (to replace Kane) and a new City Council member from ward 4 (to replace Dixon).