"Captain Fantastic," "Spirit of '76" and "Surfer Champ" are henceforth banned from your corner grocery shop in Fairfax County.

Without debate or comment, and faster than the scores whiz upward on the popular pinball machines, the Fairfax Board of Supervisors yesterday approved change in county zoning laws that will prohibit the future installation of coin-operated amusement machines in small retail establishments. Stores that already have pinball machines will be allowed to keep them in operation.

The action was taken in response to complaints from some of the supervisors last September about teen-age loitering and drinking at 7-Eleven stores in the county. The pinball machines were blamed by the supervisors for attracting the young people to the stores.

The new zoning amendments say that amusement machines, which do not include juke boxes, kiddie rises or coin-operated televisions, will be permitted only in restaurants, motels, hotels, bowling centers, skating rinks and establishments for other indoor games of skill.

In the future, pinball machines may only be installed in retail stores that have more than 5,000 square feet of floor space. George A. Symanski Jr., an assistant county attorney, said the 5,000 square feet was chosen as a cutoff "in order to differentiate between smaller retail stores which are not designed, and where it's not desirable, to have people congregate."

The average 7-Eleven has 2,400 square feet of floor area, according to Dan Medlock, Washington-Baltimore area division manager for the Southland Corp., which owns the 7-Eleven chain.

Medlock, who said he had expected the Board's action, did not know how many of the 84 7-Eleven in Fairfax County currently have pinball machines. He said "several, maybe 9 or 10" already have been taken out because of complaints.

"We could have gone ahead and put one in every store in order to beat this ordinance," Medlock said, "but we didn't."

Medlock said he could not say how much the average pinball machine earns for the stores, but according to several companies that lease the ma- chines, a popular pinball machine can net a store owner $45 or more a week.

Southland began installing pinball machines in its Fairfax 7-Eleven stores last April, responding to the machines' resurgent national popularity.

Both Medlock and the leasing companies take issue with the idea that pinball machines cause loitering. They say it is bad management at stores that have them, not the machines, that cause disturbances.

In other action yesterday, the supervisors approved the payment of $145,000 as the county's share of the $1.8 million operating deficit for the Metrorail operations in fiscal year 1977.

This payment was approved with the proviso that it does not bind Fairfax County to participate in future deficits.