Second Novel Blues

I’ve got a problem. I’m about to publish my first novel in a series on kindle at the beginning of the year. The problem is I can’t seem to get anywhere with the second novel. I’ve got good characters, a good plot, and a solid direction but I can’t seem to find the momentum to get started and keep going. I’ll start a draft for a couple of chapters and then lose steam. I wrote the rough draft of my first novel while I was deployed overseas. Since then I’ve written short stories in multiple genres but getting traction on a second novel has seemed impossible. Any advice would be fantastic.