I had a Nibo double flame that I had troubles with. I could refill it over and over and I would get nothing at all. Last month I went to a cigar event with a fried who was having trouble with his Xikar lighter and since a Xikar rep was there we decided to talk to him. He showed us what we were doing wrong.

First my friend was using Zippo brand butane which is not a great butane, switched to the Xikar butane.
Next is the most important, the purge, every time you refill you have to purge. It needs to be a good purge too, hold that sucker open until you can't even here any air coming out at all. Air in the tank is bad and will screw up you lighter quick.

I got home and took my Nibo that I thought was shot, gave it a nice long purse until I couldn't hear air anymore and then refilled with Xikar fluid and lo and behold it is back and working good. Purge. Very important.