did you prime the coil? they are tricky the original nautilus. bit of a learning curve. make sure to tighten down the coil to the base well. not over tight tho. then when screwing on the sleeve. you just want to make the seal. do not over tighten that part. and then you have to prime, or draw without putting it on the battery for maybe 10 times. maybe 15. I have found that turning the airflow off....as in turn it where there is no hole, and pull real good once will prime it for you. and then if you are using a variable W/V turn it down low and work your way up.
also need to check back to the chart. if you are using a 1.8 coil. then you do not need to turn a variable voltage mod up past 3.6 or you are going to get a burnt taste because the coil cannot handle that much power. but a 1.8 or 1.6 will heat up and vape faster. I prefer using the 1.8 with my Provari set at 3.4 I always get a good vape and my coils last like they are suppose to.
I just ordered the rebuildable coil from UK a few nights ago. because I agree the coils are pricey. and it basically gives you a tool to slide your new coil inside the coil housing and rewick with organic cotton. and they say it gives a better taste and better Vape production. we will see. if it works I am going to rebuild the 15 coils I have saved and not worry about buying coils for my nautilus tanks anymore. the kit was right at 30$. so if I do 10 coils I just evened out my money.
and on the kayfun, they are really nice. I built a 2.0 ohm single coil and when I want to change flavors, I just break the tank down, clean it, put new cotton in it, fill and vape. the flavor is unmatched by the kanger/aspire tanks. not even close. downfall is it sucks e-juice straight out the tank and into your lungs. maybe 2-3 times the e-juice consumption no kidding.