Yet another movie based on a beloved ancient TV series, "Leave it to Beaver" is arch and campy, and surprisingly amusing . . . for the first 40 minutes or so.

But like most attempts to pad out a half-hour sitcom to 90 minutes, this one runs out of steam before it's over.

Taking a cue from "The Brady Bunch" movies, the "Leave it to Beaver" characters seem to be stuck in the '50s, while the action is clearly set in the '90s. But it isn't as off the wall or goofy as the "Brady Bunch" films, as if the filmmakers here weren't quite sure how far to go.

Cute little Cameron Finley is well-cast, however, as the ever precocious Theodore Cleaver, whose nickname is "The Beaver" (although the character is played out more like another '50s icon, "Dennis the Menace," which had its own movie adaptation a few years ago).

Christopher McDonald takes the role of Ward Cleaver, suggesting just the right mixture of exasperation, idealism and soft-hearted common sense. Janine Turner, who makes a stunning June Cleaver, has less to do — but she does get to utter the film's most amusing straight-faced line: "Ward — I'm worried about the Beaver."

The story, not that it matters, has Beaver "sucking up" to his father by joining the Mighty Mites football team. He wants a bike for his birthday, but shortly after he gets it, the bike is stolen by a neighborhood bully. (No one ever thinks to call the police, however — in fact, this imaginary small town doesn't seem to have a police force.)

Meanwhile, his older brother Wally (Erik von Detten) begins a relationship with a girl! This is complicated by the fact that he's supposed to be fixing her up with his best friend Eddie (Adam Zolotin). (Is it really a good idea to portray 12-year-olds kissing and going out on dates, or am I just showing my age?)

As Wally, von Detten is a caring older brother, evoking the TV series' character. But Zolotin is out of his league as the unctuous Eddie, who was played to slimy perfection by Ken Osmond on the original show. (Here, he refers to Beaver as "Beavis.")

This is confirmed by casting Osmond as young Eddie's father, allowing him to demonstrate briefly — and hilariously — how the character should be played. (Barbara Billingsly, the original June, also makes a brief appearance.)

It doesn't quite work, but some of "Leave it to Beaver" is a gentle little time-waster that will probably please young children and evoke some nostalgia in their parents . . . er, grandparents.

The film is rated PG for comic violence and a couple of mildly vulgar remarks.