When the Washington Capitals opened their 12th training camp yesterday at Mount Vernon Ice Rink, winger Lou Franceschetti was in attendance for the eighth time. No other Capital, not even the legendary Yvon Labre, can match that record.

So far, however, Franceschetti can be credited only with perseverance. After each of the other camps, he has received a ticket to the minors and over seven seasons in the Washington organization he has played a mere 54 games for the Capitals.

Now Franceschetti is in a position to pluck the plumpest plum of training camp. If he proves he can do the job, he might find himself patrolling the left side on a line with Bob Carpenter and Mike Gartner.

How can someone who has failed to make the team seven straight times blossom into a winger on the No. 1 line? Partly by default, because there are no candidates who jump out at the coaches, partly because he possesses both the speed and aggressiveness necessary to complement the club's top scorers.

Franceschetti seemed headed for oblivion with a termination contract two years ago, until injuries forced Coach Bryan Murray to use him during the playoffs. He performed so well against the New York Islanders that General Manager David Poile gave him another termination pact.

Last year, starting the season in Binghamton, Franceschetti was fighting for the American League scoring lead when he was called to Washington. He was impressive in late-season games as well as the playoffs and was rewarded with a new contract that carries beyond the current season. "I sure hope I can stay this time," Franceschetti said. "I feel a little bit more relaxed this year. David made no promises; he said I'd have to earn a job. But he said we're light on the left side and if I play the way I did at the end of last year, I could be there.

"I thought about trying to move somewhere else at the end of last season, but I like the way this organization is going. We've got a lot of unfinished business and I want to be part of it. David has been fair to me; the first four years weren't as fair."

A prolific American League scorer with 72 points in 52 games, Franceschetti knows he cannot match those figures in the NHL. But he believes he can do a capable job if he is given a chance right from the start.

"It's tough when the only time you get called up is when a guy's hurt and you know you're going right back," Franceschetti said. "That was the situation the first time I came up last year. But the last 20 games, I knew it was my last shot and I tried to be consistent the way I was in Binghamton.

"I'm not going to score 40 goals here, but I think I can get 20 to 30."

Franceschetti concedes that the right guys to guarantee a big season would be Carpenter and Gartner. Franceschetti was a linemate of Gartner at Niagara Falls in 1977-78, when he scored 40 goals and Gartner netted 41. Since then, while Franceschetti has persevered, Gartner has prospered, scoring 50 goals for Washington last season.

"It would be great to play with Bobby and Mike," Franceschetti said. "I played a couple of games with them last year and I profited from it. I have a certain role and if I can add toughness in the corners on that line, and keep up with my speed, that would be fine.

"But I'll be happy with one of the four spots on left wing. It's a matter of me going out today, tomorrow and every other day of camp and proving I belong right from the start."

Fifty-five players skated yesterday. Right wing Jim Thomson was missing because of his father's illness. Center Dwaine Hutton left because of pulled stomach muscles . . . A draft divided the roster into three teams for intrasquad games, scheduled today at 9:30 a.m. and 4 p.m.