Not sure what a 3024 is. sound like a profane to me.
The 502 is a nice stove. If when you took the fuel cap off you had to force it to get the gasket to let go from the fount the the gasket is probably bad. If the cap has a screw in the middle it is called a "three piece" cap. Gasket is easy to replace once you have a new gasket and know how. It require fire to add to the enjoyment. Stores only sell replacement caps. Not a lot of money to be made selling just the gasket. If you have a one piece cap those are harder to replace the gasket, can be done but not one of the easiest things to do.
Put fuel in to just below the filler hole. Or use one the the red plastic filter funnels. Pump it up about 25 -30 pumps. Do not worry your thump will give up long before the fount will burst from over pressure. Get the beast fired up and roaring then add about 5-10 more pumps. If the cap is sealing should run for a long time. My only grip with the 502 is they do not simmer well, at least the ones I have.
Randy