Knowing When It's Just Not Working

I recently cut about 15,000 words from my first draft. I was working on the scenes leading to the climax ending and I realized that it was getting harder and harder to make progress on the story.

I realized that the story was straying too far from plausibility, which is really saying something for a science fiction story. It was becoming a chore because I was trying to steer it back "on track", and I didn't like where it was going.

At some point I just decided that it wasn't going to work. There was no saving it, and I didn't feel like waiting until I was editing it to rewrite that whole section of work. So I chopped it off and started again, proposing a "what if?" scenario to steer the ending into a new direction.

Does this violate my rule about not editing while writing? I don't think so. I believe it's foolish to keep plodding forward on a plot that just isn't working; I'm using my enthusiasm for the story as it unfolds as a gauge to how well (or poorly) the story is going. This wasn't a matter of tweaking some wording or adding some choice adjectives. It was a matter of seeing that the storyline was going way off script, and fixing it by cutting off the bad part and starting over a from a few steps back.

Doing this threw me off a little, of course, since I'm wwinding back and forward to spare a section of story that did still fit while figuring out what details I thought I had and now don't. It would also be silly to have a character or detail reappear after never being introduced because I used my delete key overzealously.

Anyone else have to cut out large sections of a story to re-steer it into a better direction? I'd have a hard time believing it is that rare of an occurrence!