I have a duel fuel lantern. After I cleaned it with denatured alcohol..it worked great. Have you let fuel sit in it for a while? http://coleman.custhelp.com/app/answers/detail/a_id/68/~/reasons-for-lanterns-not-lighting-or-staying-lit.
I need to clean the long pipe the fuel gets vaporised by the flame. The end won't come off. It should according to what I saw on YouTube.