NEW YORK (AP) _ Vaudeville isn't dead. It's just been waiting for the return of Bill Irwin to Broadway.

Last seen in these parts in the techno-revue ''Largely New York,'' the sweet-tempered clown has brought along a darker, more abrasive funny man named David Shiner for his latest big-time adventure.

Their joint effort is called ''Fool Moon,'' a meandering bit of foolish fun that looks a little lost on the large stage of the Richard Rodgers Theater.

The loosely structured entertainment, which opened Thursday, is a series of silent sketches, linked by the musical accompaniment of the Red Clay Ramblers. The five-man band livens things up aurally with its eclectic selection of songs including ''Tea for Two,'' ''I Crept into the Crypt and Cried,'' ''Love Theme from Romeo and Juliet'' and a personal favorite, the daffy ''Hiawatha's Lullaby.''

But most of the evening depends on the antics of Irwin and Shiner, who though dressed in similar baggy pants, morning coats and cone hats, have different comic styles.

Shiner is confrontational, not above direct contact with the people out front. In fact, there is so much audience participation in ''Fool Moon,'' theatergoers should be forced to join Actors' Equity when they buy a ticket.

Not only is Shiner in your face, he's often in your lap, too. The show opens with the clown trying to find a seat in the theater and crawling over patrons in the first several rows and in the side boxes. Shiner musses up people's hair, takes their coats, orders them out of their seats and carries on like a naughty schoolboy.

Enjoyment of these hijinks will depend on your fondness for seeing other members of the audience embarrassed by the rowdy Shiner. Part of the fun - and relief - comes from the fact that it's someone else - not you - he is pulling into the act.

Irwin is gentle by comparison. He's the poor schnook who's baffled, harassed, even tormented by the simplest of things - a recalcitrant microphone and its cord, a plate of spaghetti, an umbrella, for example.

''Fool Moon'' shines best when Irwin and Shiner work together on the nearly bare stage. In one sketch, they impersonate intense commuters waiting for a train. The two men do pushups and trade belly punches as they try to out-macho each other. If you needed any proof that these two scamps are made of rubber, watch as they seem to expand and contract during this brief show of white- collar one-upmanship.

The men battle with equally successful results in a restaurant scene where Shiner plays a ramshackle lothario - the object of his affection is a young lady from the audience - and Irwin is a prissy, officious waiter.

Although Irwin and Shiner are listed as creators of ''Fool Moon,'' no one is billed as director, and the entertainment's aimlessness shows. The evening never builds, despite the high quality of most of the individual sketches. In fact, it threatens to bog down in the second act, when Shiner corrals several good-natured victims from the audience to work through a laborious silent movie sketch.

Yet the show's last image is literally heaven-sent. In front of a backdrop of stars, Irwin and Shiner sit on a lighted crescent moon as it climbs to the theater's proscenium arch. It's a giddy, airy ending for a show that would have been more successful if its pacing were as directed as that final entrancing lunar glide.

What other critics said::

Frank Rich, The New York Times: To that short list of unbeatable combinations that includes bacon and eggs, bourbon and soda, and Laurel and Hardy, you can now add Shiner and Irwin.

Howard Kissel, Daily News: Irwin and Shiner are extremely engaging performers, and their bodies have the plasticity and seeming imperviousness of Silly Putty. But after a while, their antics appear a bit bloodless.

Clive Barnes, New York Post: They (Irwin and Shiner) go on and on, and on again. Rarely in the history of the American theater have so few people done so little for so long.