Hello Brad & welcome to LMF...
Get a new cap ... there is a 'deflecting shield' (allows air in but keeps fuel from going out), that is not working ... you can try pulling it apart to see if you can salvage the one you have .... but odds are you will have to get another cap... it could be that a piece got lost at one of the fill ups, or it may not have been in it to begin with... :smile:KennyV