The needle and seat outer o-rings may not be sealing on the bores.Pull them out and inspect everything again.You may have to lightly polish where the seal rides.They do tend to pit a little in this area.Good luck.
It was the rings not sealing on the needle and seat! I did an air test at 6psi and the were hissing. Put the new ones in tonight and fired up with no fountains.
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