I just hold the carto and the tip of the awl against it and tap it with the hammer. Haven't had any problems except if I get the hole to big I get flooding. But you all use thicker juice. I have to use 100% PG.
Free, I was having the same problem... tank had plenty of juice in it, then all of a sudden BLAM, burnt nasty taste... It was the carto. I was putting 1 avg to small hole in it w/the saddle valve... Then I had a lucid moment and thought ~ lets try 2 holes ~ that was better, but not good enough. I reckon the 2 holes were just too small and too high up for the M1 tank. So now I have 1 carto with 2 much bigger holes using the saddle valve and I seem to have solved the problem... I feel much better knowing that I'm not the only one this is happened to. My juices aren't that thick 70/30 pg/vg. Altho my vg is pretty thick. So we shall see if I finally can have the success that most others seem to get from the fusions..
I'm baffled as to this one... The only thing I can think of is a connection issue. Carto not making contact w/top screw??? Dunno.. BUT I'm sure someone w/more experience will come along and figure it out .. Good Luck!