When it comes to getting gasoline, the odds for all motorists are not even.

Favoritism reigns.

Rules that were written to ensure equal distribution of scare fuel are being broken routinely at a large number of service stations throughout the metropolitan area.

Consider these examples:

Employes of a Silver Spring post office have an agreement under which their private cars are filled up at the service station next door during the station's off hours.

Fourteen cars with even-numbered plates filled up yesterday, an odd-numbered day, at the Golden Shell on Annapolis Road in Bowie.

Regular customers at the Texaco station at Sheriff Road and Eastern Avenue NE come in after dark and fill up their cars.

An Oxon Hill station has stopped selling to the public entirely, serving only its commercial customers.

Bart Isenberg, assistant administrator for enforcement at the U.S. Department of Energy, said that favoring some customers over others is a violation of federal rules. Application of that principle is complex, but it is clear that what appears to be discrimination, as well as violations of the states' odd-even rules, is occurring.

But there's a catch.

"One of the problems is proof - you need to be there when it happens or to verify the circumstances," Isenberg said.

So far, despite 489 complaints, Maryland state police have ticketed only seven motorists for violating the state's gasoline purchase rules, and District and Virginia officials expressed surprise that favoritism was occurring.

The pattern of favoritism showed no geographic limits in the Post survey of 40 stations. It was an apparent in the suburds as in the inner city.

Four of five service stations surveyed along Rte. 1, south of Old Town Alexandria, for instance, agreed to sell gasoline to a Post reporter driving an automobile with even-numbered plates. That occurred yesterday - a purchase day for cars with odd-numbered plates only.

"I told the man I had the wrong plates," the reporter said. He looked at me and said, 'Well, odd, even, I can't keep track.'"

At the same time a Merit station in Northeast Washingtn pumped gasoline into several cars with even-numbered plates. Drivers of those cars told a Post reporter on the scene that they did not realize it was an odd day.

"They know what day is it," said the attendant on duty. "They just saw the short line and decided to pull in." The attendant later was instructed to check motorists' plates before selling them gasoline.

At the Golden Shell in Bowie cars with even-numbered plates were filled up yesterday because "I'm not about to get shot for a measly gallon of gas," said manager George Edwards.

"If I see a carload of guys who've been waiting in line with the wrong plates, I might just get the tar beat out of me if I say go away.'

Favoritism found by Post reporters was strongest at stations where dealers have spent years building up their clientele.

It was least common at the self-service stations where the most attendants work behind glass windows and have little contact with customers.

Another important element in the favoritism story is the motorist's behavior.

"If they're on empty or they're nice, yeah, we'kk give it to them," said Bruce Mooers, who works at Mitch and Bill's Exxon, River and Falls roads, Potomac.

"If they're smart-alecky, we'll say, 'Sorry, wrong day.'" he said.

Among those buying gasoline yesterday from Mooers was a chauffeur at the wheel of a Fleetwood Cadillac. It had an even-numbered plate.

For the fill-up, the chauffeur handed Mooers a 50-cent tip.

At the Capitol Hill Exxon station, the pumps closed at 11 a.m. yesterday. But some cars were sold gasoline after that.

One of them drove a Renault Le Car with a New York license tag.

"This guy here called the station and said, 'I've got to New York today,' explained Herb Stanwood. He told the man to bring in the car for gasoline.

"We're human about it. If people are in a jam, we take care of them. Doctors. School buses. Day care busues. We serve them all day if we can."

Stanwood said he sometimes allows regular customers to buy gasoline after his pumps are closed. "I don't see anything wrong with that," he said.

Favoring some motorists over others is a matter of judgment, he said.

"Some people come in here with a sob story. We might let them have gas. But we turn people down all the time [if their story doesn't jibe].

"This is not IBM-computerized and impersonal. This is a gas station operated by real human beings," Stanwood said.

Customers who receive preferred treatment at Washington area stations sometimes feel guilty about their good fortune.

"It is unfair, really," said James Hardy, an employe of G. A. Eberly Plumbing. He had just bought gasoline at a Shell station in Oxon Hill where the manager has a special lane for commercial vehicles.

Russell Holiday, who manages the station on Livingston Road, defended his pratice. 'Some of these guys get $10 an hour and if they're waiting for two hours, they're losing money and the company will eventually make you pay for it.

"We don't want a higher electric or plumbing bill, so we give them gas," he said.

The more than 80 workers at the Silver Spring post office branch at 110 University Blvd., can thank post office manager F. Thomas Hewitt and station owner Kathryn Miller for helping them get gasoline easily. Shortly after motorists began lining up for gasoline at Miller's station, which is next door to the post office branch, each postal employe was issued an identification card. The card enabled the employe to buy gasoline during the afternoon hours, from 1:30 p.m. to 3:30 p.m., at Miller's station.

"We [Hewitt and Miller] worked it out together," the station manager said. "These are really private vehicles . . We limited each of them [postal workers] to one car . . . I figured it was the fairest thing to do."

Miller said he extends that same afternoon buying privilege to some other commercial customers, including a Washington Post route manager, who buys gasoline for two Post trucks at the station without waiting and for his private car.

Commercial customers who gas up at Bob Hutchinson's station in Oxon Hill are philosophical.

"It's just like all the congressmen and senators who get gas when they need it," said Gary Hurley. He arrived at the station at 7 a.m. yesterday with Keiith Hamilton in Hamilton's black van. Manager Hutchinson closed his station to the public July 1. Now he sells only to commercial customers.

He said he takes "care of the people who take care of me."

At another Oxon Hill station, Shell manager Holiday defended the special gas lane he has for commercial vehicles. Companies must take care of their customers, he said.

"All companies operate that way. If they're not, they're stupid," he said.

Concern about keeping regular customers in gasoline was a common threat in the examples of favoritism found by Post reporters.

"I don't give a damn about the public - I care about my customers," said Fred Ince, owner of a Texaco station at Sheriff Road and Eastern Avenue NE.

"They kept me going when I had gas. I keep them going when I don't have [enough of] it," Ince said. He said his regular customers can come in after dark and fill up their cars with gasoline.

Gasoline fill-ups can be obtained at many stations routinely when motorists take them in for maintenance. Robert Ottey, who operates a Shell station on Lee Highway at Lorcom Lane in North Arlington, will pump gasoline into a customer's car when it is left thhere for an oil change.

"I don't make a point of it," he said. But the option is there, if the car's license fits the even-odd requirements, he said.

Other dealers are more flexible.

When Doris Ait of Greenbriar drove up to the Arco station in her neighborhood yesterday, she bought $16 worth of gasoline, without having any repairs and without odd-numbered plates on her car.

"I'm a regular customer," she said, when asked hoow she had been able to purchase gasoline on an odd day. "I deal here on a regular basis."

Ait was the only even-numbered customer observed buying gasoline at the station yesterday.

Not all stations bent the rules, however.

In Bowie, the Bel Air Amoco scrupulously turned away the evens.

That included one man who had waited in line for 20 minutes before learning that he was an even on an odd day.

"I brought the wrong car," he moaned.

Evening Gasoline Hours

These District of Columbia stations will be open from 7 p.m. to 9 p.m. today through Friday with extra gasoline made available to them from the D.C. government's set-aside allocation:

Newman's Texaco, 5001 Georgia Ave., NW.

Mack's Service Station (Amoco), 801 M St., NW.

Boulevard Gulf, 4885 MACARTHUR BLVD., NW.

Rock Creek Gulf, 1827 Adams Mill Rd., NW.

Yuen Exxon Service Center, 1800 Rhode Island Ave., NE.

Anacostia Exxon, 2255 Martin Luther King Ave., SE.

Douglas Heights Exxon, 2125 Alabama Ave., SE.

Duvall's Sunoco, 3341 Benning Rd., SE.

Telephone Help

Following are telephone numbers of agencies providing information to deal with gasoline emergencies:

District of Columbia "hot line": 628-3181, staffed from 9 a.m. to 8 p.m.

Prince George's County "hot line": 779-1151, staffed around the clock.

Bowie area gasoline hotline: 262-6262, a recorded message listing operates daily, reaturing a recorded message listingn names, locations and hours of gasoline stations.

Frederick County motel/gas hotline: (301) 663-8687 or 662-2126, staffed 24 hours a day.

Anne arundel County "hot line": (301) 263-2681, staffed from 6 a.m. to 9 p.m. daily.

American Automobile Association: 225-5000. Officials said AAA members may obtain small quantities of gas or be towed to a nearby station if they are strained.

Flag System

Washington area service stations have been asked to display special flags, noting the availability of gasoline.

A green flag means leaded and unleaded gasoline are available.

A yellow flag means only leaded gasoline can be purchased.

A red flag means a station's pumps are closed.

Gasoline station owners in the District of Columbia can pick up flags at the Munsey Building, 1329 E St. NW, Room 1258. CAPTION: Chart, Daily Gasoline Guide, By Dave Cook - The Washington Post