Atwood hot water tank wouldn't stay lit...

As the title states, my Atwood wouldn't stay lit when we arrived at the site earlier today, I searched this forum and found that many resolve the issue by cleaning the orifice...so I slid the air mixture adjustment tube forward and gently ran some Emory cloth over it...viola ! The flame roared and I thought I was good to go...or so it seemed...I've had to go out and clean the orifice several times since then...

Is there junk in the lines or does the orifice need to be unscrewed and cleaned with something like a torch tip cleaner ?