It sounds like you are not getting enough e-liquid into the wick of the atomizer. Tell me, when you put on the cart do you drip 2-3 drops of liquid into the atomizer first? That will help the e-liquid wick up into the atomizer.
Plus, I agree with mwa102464, carts
suck. FWIW: even with a cart, my experience was that you can only vape it for about 5 minutes before needing to top off the cart again... so how often do you top off the cart?
Try dripping instead:
• take one cart and empty the filler out of it
• put 2-3 drops of e-liquid directly on the bridge of the atomizer (the mesh hump that sticks up in the middle)
• put the empty cart back on and vape
• you should be able to get about 10 drags before you need to put 2-3 more drops in again.
Good luck!
ps, I never clean my atty's, I just blow them out once in a while.