So, just have a NOS Radius 39, I fill the spiritcup full, let it burn til empty, pump 5-8 strokes with the airscrew tightened. Get a blue flame, but just for a sec or so, then the flame blows itself out. Still got pressure in the tank. I did try putting a wiremesh in the riser, but that did not help. Any suggestions?
Looks like velocity of vapour/air stream is too high. Check aperture diameter of jet. Best Regards, Kerophile.
I've seen this problem with modern manufactured stoves. Small pieces of loose solder can be floating through the system interrupting vapor flow. Can it happen with an NOS Radius? I don't know. What happens when the flame blows out? Is there vapor flow that can be relit immediately? I'd probably start by emptying the fuel into a clean jar and seeing if there is any dirt or pieces of solder. Then take the burner off and remove the jet and use compressed air to make sure the burner tubes are clear.
Low pressure? My stoves won't light if pressure isn't enough to sustain a flame. Crud can interrupt things. Maybe remove jet and flush system. Duane
A windshield would also help to get the burner heated when working outside in Winter or with side-winds
