Burner issues.....

So I'm at a loss here. Got an old turkey fryer burner from a friend. It's seen some weather and is a bit rusted. It looks like Bayou Classics BG10 burner, but with no air shutter. My issue is got an 20 psi high pressure regulator with a needle valve flow knob on it. So I hook it up today. I'm either getting small yellow flames or when I turn it full throttle it has blue flames at the bottom and a huge yellow flame above that. I can't seem to figure out how to get the nice steady blue flames. Some advice would be very much appreciated. Thanks in advance.

Replace the missing air shutter. Better yet, get a different burner entirely. This one is a much better burner IMO:

http://www.amazon.com/dp/B0009JXYT6/?tag=skimlinks_replacement-20

Disassemble it and take a wire brush to it paying particular attention to between the vanes. I bet that will take care of it. Bits of rust will fill in between the vanes and reduce gas flow, which in turn makes it difficult to suck enough air in for proper combustion. Yellow flames usually mean not enough oxygen is present. I will only close the shutter down when I want a cooler flame.