Dave Marr will be be most visible and vocal personality this weekend on ABC-TV's broadcast of the PGA Championship from Pebble Beach (WJLA-TV-7, 5:30 - 7 p.m. Saturday and 4:30-7 p.m. Sunday).

Marr has come a long way since he slept in the back of the golf shop at the Winged Foot Country Club in Mamaroneck, N.Y., as an assistant to Claude Hagmon, the 1948 Masters winner. "Little Davey," as they used to call him, won the 1965 PGA Championship and since then has parlayed his one major title and an amiable personality into marketability.

Marr is golf director at the Princeville Country Club in Kauai, Hawaii, but this is only one facet of his busy life. He works for several corporations as a "golf lobbyist."

"It's something new", he says. "A lot of companies don't sell directly to the public but to the manufacturers. I take their representatives out on the course. Sure, I give them a few tips, but mostly it's for fun. I guess you could call it a form of 'lobbying' but it's the greatest sales method I know."

As the analyst-in-residence for ABC's golf broadcasts. Marr does a lot of homework. He was at Pebble Beach for a week before the tournament began, studying the golfers and their styles.

"I know the tour regulars," he says, "but I have to watch the new ones coming up to see if they have changed anything. To a tour golfer, the swing is everything. A Johnny Miller or a Jack Nicklaus may not be aware that he's doing anything differently, but when I see them in slow motion I can tell something has changed. I'm not in broadcasting to criticize. I merely observe."

Marr says the most classic swing among current golfers belongs to Tom Weiskopf. "Like Sam Snead, he's so physical," Marr explains. "But for the average golfrer, I'd pick a man like Gene Little.He gets it done with a minimum of effort and he must be good if we look at his record."

The club pro at Marr's course in Kauai is Sammy White, a familiar name to late '50s and early '60s baseball fans. "Maybe you remember White as a catcher for the Boston Red Sox," Marr said. "The funny thing is that Frank Sullivan, who was a pitcher for Boston at the same time, is a golf pro down the road."

At 43, Marr is bullish on golf and its benefits.

"The game opened up many doors for me," he said. "I'm no Nicklaus or Palmer. I had to merchandise what I had. I'm lucky to be in golf.

"It enabled me to meet people such as Presidents Eisenhower and Ford. Really, my biggest thrill when the PGA was at Congressional last year was meeting Judge John Sirica. He's been my hero ever since Watergate and I have an autographed picture of him on the most prominent wall in my house. I'm a lucky man."