Montgomery County school board members, in an effort to avoid the type of major controversy that erupted recently over the leasing of an abandoned public school building to a private school, recommended last night imposing strict new limits on the leasing of unused county schools.

Three of the four board members present at last night's meeting proposed that private schools either be barred from renting public school buildings no longer in use, or else that they be permitted to lease them only if all county efforts to locate other tenants fail. Under the proposal, even if the private schools do win permission to lease the structures, they must demonstrate that no harm to the public schools would result from the lease.

The three members--Marilyn Praisner, Blair Ewing and Robert Shoenberg--agreed to ask a county government task force committee meeting today to produce guidelines that would exclude private schools as possible tenants or rank them at the bottom of a priority list because, as board president Praisner said "public schools should not be in the business of underwriting private schools."

The task force committee, headed by former Maryland State Board of Education President Richard Schifter, was appointed by County Executive Charles W. Gilchrist after a major protest that followed Gilchrist's leasing of the former Larchmont Elementary School in Kensington to Grace Episcopal Day School. Opponents of the lease, who included board President Blair Ewing and County Council President David Scull argued that the private school would interfere with the county's major school busing plan designed to foster integration in that area.

The fight over the lease eventually was settled last month when Grace Episcopal officials agreed to sharply limit the number of students it would accept from the public school integration plan area.