new carburetor installed ran once, now wont start

Hi,

I installed a new carb on my Echo SRM225 line trimmer and it started and ran great. I ran t for about 5 minutes or so and then shut if off for a couple of minutes, and now it will not start. I have no idea what is going on. Any help would be greatly appreciated.
Thanks

new carburetor installed ran once, now wont start