Wesley Lum, 26, knows he's different and it angers him.

He lashes out at his parents and runs away if he's not supervised carefully. He has no friends and little to do besides eat and sleep.

Lum is emotionally disturbed and mentally retarded, and the combination makes him ineligible or unsuited for programs that focus on just one of his two handicaps.

For years his parents have tried to find a place that will help him. Recently they and Wesley visited Concord, a residential facility in Yellow Springs, W. Va., that teaches both vocational skills and provides psychological counseling to people like Wesley.

The Lums were told that the cost, approximately $17,000, would be paid by the state. Then, last week, they learned otherwise.

"I don't understand it," said Mary Lum. "Suddenly we were told that the money had dried up."

The reason Lum will not go to Concord as planned, nor will another 32 emotionally distrubed, mentally retarded adults attend special facilities, is an eleventh-hour budget switch.

The state legislature appropriated, and Gov. Harry Hughes approved, $655,619 for 13 community treatment placements and 33 purchase-of-care slots, which are residential facilities in other states.

However, only the community treatment, in which individuals live in a supervised residence and have daytime vocational training, will be implemented, using about $200,000 of the funding. The rest of the money will go to maintain existing programs, which were not included in the fiscal 1981 budget.

"We cannot, by state law, overspend our budget," said Bernard Carpenter, who was appointed director of the state Mental Retardation Administration this spring. "When I became director, I found the costs of actually doing business were much higher than the funds we had available. The unhappy consequence is that we cannot service new programs for which there is a real need."

About one-third of the 46 dual handicapped adults are at home idle; another third have limited, daytime activities outside their home. Others are in private or public insititutions, most of which cannot handle their particular needs.

"We will try to catch up with people in FY 1982 that we couldn't fund in '81," said Carpenter.