What to do now? This cart still has .6g left in it and was hitting before (although was wispy compared to other carts)!
It gets hot... maybe the top heater is dead? I have bad luck with the top heaters in these
Sorry you're having trouble. OK, a couple of issues here. Let's go after one at a time? First off, what power cart are we talking?
The heaters have no connection to the draw, it should draw cold and not even attached to your trusty Omicron. If you've sure the upper tube is clear, it has to be the lower one almost certainly as flooding the furnace enough to completely block flow there in the face of heat is, I believe, unheard of. You need something smaller in diameter but shorter for the job.
I generally advise against needles point end down, too easy to scar the heater, I hope yours is at least eye end out? IMO most anything else (I use plastic covered copper wire or nylon fishing line usually). Anyway, same drill as before, gently insert it and remove it to wipe clean and repeat. The heater is about 1/2 inch up there, be careful. Unfortunately the lower tube fouling is not from concentrate vapor condensing like the flue is, vent jams generally come from flooding and can point to seal leak issues. Getting it clear and running well is the first step in that project.
You might want to practice a bit poking up the vent on a new (or well working) cart if you have one. Getting 'the feel' is important as is finding the heater location so you can avoid it. Poking through baked in oil is not a good time for that.
Having .6 left obviously shows you had even more at one time, which is probably contributing to the leak. Half a grem at most is recommended, seal leaks are the typical downside of loading more.
To the heater issue, I assume by 'top' you mean the outer or reservoir heater rather than the inner or vaporizing one? Standard carts with concentrate properly loaded should be pretty immune to burn out the other heaters seem to fail more often since they run hotter by far....and they almost always die from low production due to fouling. More than one would be strange indeed. Again, what's your usage pattern (do you sip or chase serious clouds?), and what power level are the dead carts?
TIA
Good luck.
OF