Flooding could be from a variety of things. If it is the
tank causing it then it is almost with certainty the top oring. They can be a little tricky to get installed but they will go in there.
You can also get flooding from technique, each draw creates a vacuum on the tank and tries to bring in liquid so long slow light draws bring in less while vaporizing more where a short stiff draw with greater vacuum on the tank pulls in more and has less time for vaporizing.
When priming the tank for its first use you can over prime the cartomizer which will of course make it flooded, it also seems once a cartomizer is flooded it can tend to stay that way unless you unflood it. One easy way to do this if you have the refilling drip tip is to use it to push the cartomizer down like you are going to fill the tank but stop when the holes in the cartomizer are just outside of the bottom cap. That drip tip is long enough that at this point you can still vape with it but since the holes are on the outside no more
eliquid will be coming into it.
You can either blow it out into a paper towel or put the tank back onto a device and vape it clear, just be careful as the top is not sealed now so it needs to remain pretty much upright until you push the cartomizer back in.