Trying to summon the motivation

Do any of you remember the drive and force that you felt years ago when something needed to be done?
I do. I used to take things as a challenge and rise to meet it. I was motivated to do things.
Many times nowadays, it just isn't there. Part of me wants to but laziness creeps in. I want to get out of that rut.
I have car projects out back. I have stuff to do on the house too.
Years back when I had gained a bit of weight, the wife and I decided to get in shape. We ate better, joined a gym and in a few months, I was down 30 lbs and looked much better. Once I got to the goal, I actually liked the journey getting there and in some weird way, thought it would be fun to do again some day.
Winters are the worst for me in terms of kick starting my motivation. Is it the same for you? The gold and gloomy skies make me want to stay inside despite several tasks that need attention. It doesn't even snow here so I can only imagine what it is like for those guys that live in it.
I've read that some people just get out and casually start doing things in the hopes that it will inspire them to keep moving. That does work but sometimes I'll still just turn around and come back inside. I spend too much time online already...I need to ignite my fire and I don't know what it is.