Larry Ringer, the Middle Atlantic PGA Player of the Year in 1978, broke out of a season-long slump yesterday with five birdies in a six-hole stretch for a two-stroke victory in the MAPGA championship.

His final round 68, four under par on Washingtonian's Country Club course, gave him a 54-hole total of 214, two under par. Tied at even par were Woody FitzHugh, the 36-hole leader who skied to 75 yesterday; Mel Riffman (75-68-73); and Greg Overton (71-74-71).

The Ringer on the tight-driving, wind-blown Washingtonian course yesterday was hardly the same man who knocked two balls out of bounds, one in a lake and made four double bogeys in his first two rounds.

Ringer, pro and coach at the U.S. Naval Academy, returned to his home course and practiced for 90 minutes after his 74 Friday left him five strokes off the lead.

Fitz Hugh had predicted correctly that all he would need would be an even par 72 to win the tournament, the $1,000 first prize and the privilege to play the PGA tour for a year.

Since suffering a back injury in the early '70s, the 34-year-old Ringer has had limited range with his swing. Already a right-to-left player, he has a short, quick swing that has only served to perpetuate sweeping hooks. A stretching and flexibility program has eased some of his problems and allowed him to swing more fully.

Early in yesterday's final 18, playing just in front of the leaders, Ringer struggled, missing three of the first seven greens. Yet he stood only one over par for the day.

Then everything came together. He dropped a 12-foot birdie putt on the ninth green. "That was the biggest putt, the key," he said later. At the short 10th, Ringer left his flip wedge 15 feet short of the hole, straight out on line, and barely missed the birdie.

From there, he drilled four successive birdie putts, starting with a 30-footer on the par-3 11th. He followed with a 12-footer on the par-5 12th, then a 10-footer after flirting with water on his tee ball at 13 and a 16-footer at the 14th. That put him two under par for the tournament and, after getting up and down from a trap on the next hole, he parred in.

The 13th was one of the holes Ringer double bogied earlier. Teeing off with a three-iron, he hit the ball thin and barely cleared the water with the aid of a strong tailwind. It was his last mediocre shot of the round.

At 17 and 18, where he had used his driver and twice hooked out of bounds in previous rounds, he played a two iron on his tee ball and routinely made par.

On 17, Ringer pulled both a driver and an iron from his bag. Then the wind, which had been at his back, died down and he flipped the driver aside.

Ringer had played the PGA tour and said that despite the exemption from qualifying school, he does not plan to play it again. "I can't win out there," he said. "I know that. I have a hard time making a check in this section."

FitzHugh, 27, assistant pro at Washington Golf and Country Club, would have grabbed at the opportunity to play the tour.

A two-shot leader, he started off strongly with a perfect drive and six-foot birdie putt on the first hole. But his round started going downhill when he hit trees twice on the par-5 fourth hole, three putted from eight feet for double bogey on the par-3 sixth, and bogied No. 9 for an outgoing 39.