Just tried to light the 300X to take some pictures but it didn’t go to plan. Fitted new mantle, soaked and lit the vaporiser heater and let it burn for a good few minutes with the pressure release valve open. Closed the valve and gave five of six pumps and it looked promising. The mantle went from black to white, the lamp was hissing but no pop from the mantle so as I was waiting for it to burst into life I quickly turned the control cock to prick the vaporiser then all of a sudden fuel started to bubble out of the pump rod housing so I released pressure immediately and of course it stopped. I’m guessing it’s the one way valve playing up but it looks good with new washers etc. Any ideas ?
Empty the tank of fuel, pump some air into it and pull the pump rod of the tube. Then pour a little water into the tube and you will no doubt see bubbles due to air leaking out of the valve at the bottom. Either the washer sealing the non-return valve to the base of the pump tube is bad, or the little rubber pip inside the non-return valve is bad. I always find properly seating the little pip to be a pain due to its small size.
Thanks for the help. Under half full of fuel. Did as above suggestion and yep, bubbles. I changed the valve to pump tube washer for a slightly thicker one but left the little pip washer alone as it was well seated inside it’s cup. Again, no luck, this time the pump tube filled with fuel so I’ve just got to play around with it I guess. I said at the beginning of this restoration that this lamp is fighting me all the way and looks like it’s still got more grief in store for me even at this late stage.
Sometimes you just have to dismantle and re-assemble the NRV until it seats itself properly - including the pip which is the little blighter that's probably causing the problem. The other possibility is that there may be an old seal lurking at the bottom of the pump-tube which you haven't noticed. It's worth checking...
