I completely agree about the motivation, really what I am working on is huge as it covers ten years and 130 items that need at least 100-150 words each. Arggh I guess perseverance will pay off when I am finished and don't have to do it anymore.
I think you might be approaching your task in the wrong way. Instead of looking at it as a huge project that you have to attack, break it up into smaller parts. That way the task might not appear as burdensome as it appears to be to you now. Whenever I would run a 12 mile run, I would not say that I have 12 miles ahead of me. Instead I would break the run up into 4 equal parts of 15 minutes each. That way the run would not seem as formidable. You should do the same.