yocan coils wont get hot enough for proper hit

[fin]

i don’t know what’s wrong with my yocan evolve plus xl. i changed the coils one day and then i wasn’t getting as big hits. i changed the coil again thinking there was a problem with the coil itself but nothing changed. usually after a few hits the coils would be too hot to touch but now they don’t seem to reach as high a temperature. it still heats up enough to melt the oil but with little vapor. i took the atomizer off and connected the coils directly to the battery by placing a small slit of paper between the threads and the coils would reach a much hotter temperature however, this causes the mouth piece to have quite a bit of airflow resulting in a poor hit. i’m not sure what else to do or what exactly is wrong with it. any solutions or suggestion are welcome. thank you!