Hello people an thanks for your ongoing help. I have bought a 236 coleman lantern and unlike my 242b lantern air comes back out of the plunger rod if i lift my finger off before tightening the plunger rod back up. Once i have filled font with pressure and screwed the plunger up firm again it holds pressure well. Is this an issue and if so what do do about it ? Thanks in advance
It’s how it’s supposed to work. If the ball bearing in the check valve is new(ish) it may form a very tight seal, but the true seal is the screw-in stem. Tony
Other than a quick puff of air from the compressed air remaining in the pump tube after releasing your thumb, if there is continuous air pressure releasing through the pump before closing the valve then you have a bad check valve. I just replace one in a NOS fount that should have been good but was not. It will now hold pressure with the pump screwed out. Tightening the pump and closing the air stem in it's seat in the check valve is a safety feature should the check valve fail. There are many possible ways that the check ball will not seal and recently I've seen chunks of Verdigris, plugged with rust, and old gooey/hard dry oil. As the end user, only you can decide what you are willing to accept/risk. Mike
Old fuel residue and oil from the pump cup can make a CV ball stick. With the stem out, if you take some carb cleaner and spray it down into the pump tube, let it soak for a little bit. (still leave the stem out) use the pump and force the carb cleaner through the check valve. You may have to do this a couple times to free up the little BB.
I will chide myself for an incomplete answer (above) to your question. The explanations that follow are correct. If the ball bearing in the check valve is pitted by rust, stuck by fuel or oil varnish, or impeded by grit, the check valve will not operate correctly. Best regards Tony
