Water is not just going to come out when the machine is off when using a tank. There is no pressure behind the water to push it. Second get rid of the extra length of hose you have. You want the shortest distance from tank to washer. Also your reducing too soon. Reduce at the pump if you can, so run 1in all the way to the pump and reduce it at the pump. I would also take off the inline filter on the pump it restricts flow a lot. By pluming the unloader to the tank it helps in priming by give the excess air a place to go but its not necessary.
Make sure your not sucking in air anywhere, if you sucking in air it wont work. Hook the pump up to the spigot via garden hose, and actually run the machine. This get water in the pump and help prime, Next remove garden hose and hook back up to the tank. Pull the starter a few times (with the switch turn to OFF). You should see the water starting to move closer to the pump. With every pull you suck out all the air in the lines. Once you get most of the air out, start/run it.
Are you planning on putting this on a trailer?