Ollis Jon Mozon Sr., 52, a retired D.C. public school teacher and counselor, died of cardiac arrest Wednesday at Washington Hospital Center. He had retired this year from Maury Elementary School, where he had been a counselor since 1965. Before that he taught for eight years at the former Morgan and Buchanan elementary schools.

Mr. Mozon was born in Sumter, S.C. He came to Washington at the age of two with his family. A graduate of Cardozo High School and the old Miners Teachers College, he later received a master's degree from American University.

He had served in the Army during the Korean conflict and worked at the Main Post Office here before joining the school system in 1957.

Mr. Mozon was a member of the Mount Carmel Baptist Church, where he had served as a deacon. He was an Explorer adviser of Post 511 of the Boy Scouts, sponsored by the church, and had been a member of the District Exploring Committee, where he had directed Exploring Training. His awards including the Silver Beaver, the Boy Scout's highest honor.

He is survived by his wife, Vivianne, of Washington; four children, the Rev. Ollis J. Jr., of Washington, Leslie, of Daytona Beach, Fla., Nadine, of Terre Haute, Ind., and Monica, of Washington; his mother, Amanda Mozon, and a sister, Josephine Cauthen, both of Washington, and a stepbrother, Charles Hanna of Baltimore.

The family suggests that expressions of sympathy be in the form of contributions to the Mount Carmel Baptist Church Building Fund.