Once your tank is cleaned, prime your coil.
All cotton coils have to be primed well with juice. If they are not primed well the cotton will burn. Once the cotton is burned the burned taste doesn't go away.
To prime the coil, drop 5-8 drops (sometimes less/more depending on the size of the coil head) of juice right inside the coil, another drop of juice in all the holes on the side of the coil. Put the coil in the base, fill the tank and screw the base back onto the tank. Once you put the tank on the battery give it several unpowered primer puffs. This will make sure the wick is fully saturated.
Turn you voltage/wattage down, tank a few hits, bump it up, couple more hits. Repeat until you find your "sweet spot". If your vape starts to taste burnt, dial it back down.
Kangertech suggested operating range for their OCC coils. These are not hard numbers. You can run them lower/higher if you are not getting a burnt taste.
Horizontal OCC Coils
0.5 Ω coils - 15 watts to 30 watts.
1.2 Ω coils - 12 watts to 25 watts.
Vertical OCC Coils
0.2Ω coils - ? watts to 80 watts
0.5Ω coils - 15 watts to 60 watts
1.2Ω coils - 10 watts to 26 watts
1.5Ω coils - 10 watts to 26 watts