To cut it very short, the lamp turns into a raging inferno when the valve control disc is turned with the arrow down. If turning it up (so the valve should be closed) the lamp works almost normally (pulsates badly every second but works). I took apart the control mechanism, the eccentric block is being moved correctly so the only thing I haven't disassembled is the foot valve. Can this be a case of a weak spring? When testing with the lamp cold the valve cuts off the fuel just fine.