Steve Fellinger, 22-year-old University of Maryland senior, shot two-under-par 68 for 139 at the halfway point of the Middle Atlantic Golf Association Amateur championship at Washington Golf and County Club yesterday.

Fellinger, who makes his home in Niagara Falls, Ontario, and has one semester to go for a degree, had a three-stroke lead over Marty West of Columbia County Club and Paul Erhardt, defending champion and first-round leader.

A total of 63 will compete in today's third round with the low 40 and ties finishing up tomorrow. Yesterday's cutoff was 159.

Fellinger was out in 33 and home in 35. He birdied the first and second holes, canning four-footers. He made a three-foot putt for a birdie on the fifth and his first bogey on the seventh when he hit a wedge shot over the green.

He had a birdie 4 on the dogleg 15th with a five-foot putt and finished with a bogey on the 18th when he caught the trees.

Erhardt had a chance to stay two strokes closer but he double-bogeyed the par-4 18th. He was short on his second shot, sculled a chip 20 feet past the pin and three-putted. He required 37 putts yesterday as compared with 32 in his round of 67 Thursday.