Okay, here's another in a long list of questions I keep coming up with...I bought a Dubro Kwik Fill Fuel Pump and it comes with the fuel cap fitting. I bought a gallon of Cool Power fuel from my LHS. When you unscrew the cap from the gallon of fuel there's another red cap under it which sits down in the throat of the container. What's that for? Do I discard the red insert cap and drill my 1/2" hole for the adaptor into the main cap or what?