It's not that the outline's killing my inspiration - the parts I'm happy with I'm very eager to write. And writing without an outline doesn't work for me personally because if I do that I always end up with something plotless.
The problem is that the outline is maybe 70% good and 30% bad. It doesn't ring true, it doesn't have unity from beginning to end, there are places where I have no idea what should be happening (which suggests the greater underlying problem that my worldbuilding is missing details) and at 60 chapters its probably too long (my chapters tend to run about 3,000 words). This is the second version of the outline, and the first revision improved it, but not enough.
So I think Christine N. and azbikergirl are right, I have to figure out where it's going wrong. That's a complicated problem because it's not like the plot went awry at a particular point, it's that the underlying pattern isn't strong enough, I think. I guess I'll go stare at it some more and try to see what's wrong, but if anyone has and outline-revision or inspiration-capturing technique tips, please share.