u/Gesischtiwaden

I inherited my grandfather's Coleman lantern recently, and I decided to try to use it. My dad has Colemans, so I borrowed some fuel to use. Unfortunately, the lantern won't stay lit for more than a few minutes and never seems to go full bright. The pump holds good pressure, the mantles are brand new (burnt in already), and there's clean white gas in the tank. Dad has forgotten more than I've ever known about gas lanterns and I don't know what to even search for on YT. Any help is appreciated.

EDIT - found my problem, gas valve wasn't fully open. Thanks guys