duel fuel coleman problems

hi iv a coleman duel fuel lamp.when i pump it i cant seem to build up compresion in the tank.iv unlocked and taken out the pump and it and the rubber seem fine.any one out there with any ideas.nights are getn colder and darker

lubricate the pump rubber with some grease and give it a try. You might have to replace the rubber. Easily ordered on ebay.

Kev

thanks il try put sum oil on it and take it from there