Folks, picked this lantern up cheap. Great condition save for one issue or feature, hence this question. When I unlock plunger and pump with my finger over the hole in the Center of the plunger it pumps and you can feel the pressure. But as soon as I take my finger off the plunger to lock it down, the air escapes from the tank through this hole. And consequently light dims. I have a dual fuel stove and this does not do this. Is this a safety feature on lamps or an issue with some aspect of the pumping mechanism? Thanks,
@JohnL The Coleman 285 2 mantle has a air check valve at the bottom of the pump tube. It’s actually a ball valve that prevents air escaping from the fount when using the pump. This ball valve is not meant to be a perfect seal and quite often they leak a bit, this is normal. There is an air stem installed in the pump tube, with the air stem sliding into the pump rod. The job of the air stem is to screw into the check valve to make a perfect seal with the check valve seat after the fount is pressurised, thus preventing any air leak. To pump up the fount, the pump knob must be turned approximately 2 full turns anti clockwise. This opens the check valve/air stem seat thus allowing the pumped air to enter the fount. After the fount has been pressurised, the pump knob must be turned clockwise until you feel it stop turning, don’t use excessive force. This causes the air stem to seal against the check valve’s seat thus prevent air escaping out via the pump ball valve. See item 17 on the following diagram. Provided, after pumping, you’ve used the pump knob to seal the air check valve and air is still leaking, the air stem seal with the check valve seat is probably leaking. The remedy may be to clean the seat by soaking the check valve and air stem, in situ, using acetone or a carburettor cleaner. If this doesn’t work then the next step maybe is to remove the check valve for a thorough clean. Hope this helps Cheers Pete
You can probably unstick the little ball in the check valve by blasting it with carburettor cleaner spray. As a temporary work-around, keep your finger over the hole until you have screwed the pump valve shut. Those check valves come out a lot easier than the older ones as they have an o-ring seal. Just use a very large flat screw driver.
@AussiePete, didn't have carby spray at hand but did have a can of compressed air...used to great effect, problem solved! Thanks all again for your quick responses.
