“more” not working

I just installed wordpress, and when I make a post, the <!–more–> tag doesn’t work. I put it into my post, like so:

Test

<!–more–>

Does it work?

And when I click the post, it gets a 404 page. It won’t show the content in <!–more–>.

This is bugging me, as I make really long entries, and I don’t want to clutter the page.