My lack of motivation to start a task seems to be because I have forgotten to day-dream a bit about the future benefits of completing the task i.e. what it would feel like to actually finish the task and to enjoy the benefits.
Gold Panning Example: I really don't want to go panning for gold. The water is cold. It's hard work. It's windy. It's cloudy. I rarely find much anyway...
So, I imagine what it feels like to actually find a 1/4 oz nugget. Wow! What a trip! I did it! I remember what it was like the last time I did it. It was great! Now it's easier to start.
So far I have focused on "starting a task." Not continuing it, nor finishing it. I find that once I have finally begun a task, it took so much effort to start that I am very reluctant to stop.
When I recognized I had two different problems (not one), things seemed quite a bit easier. I just remember what it will be like when I succeed, and once I am going, I remember that it is easier to continue than to quit.
Hope that helps.