I try, but have not succeeded, to install a new leather pump cup on an old 111 roarer burner. I thought this should be straight forward, but it's anything but that. It was easy enough to remove the damaged pump cup from the pump rod, and fix the new one on the rod, but to fit the pump rod with the new cup in to the pump tube in the fuel tank, has so far been impossible. Its seems to be to big, but its a 14mm one and the seller informs that its the correct cup for an 111 stove. I have been advised to soften it in paraffin or oil for some time, to soften it, and have done that, but it will still not fit in the tube. Is there a trick I dont know of? I obtained 5 pump cups, so I can afford to ruin one in the process, but I am totally at a loss here.
@Northman Reverse fit the pump cup seal on the pump rod and then insert the pump cup seal into the pump tube and leave for 24hrs to set its shape. Then remove and refit the pump cup seal on the pump rod the correct way round and this should then be easier to fit. Pharael.
Yes, fitting a new pump cup is quite a ritual. The way how I do it has never failed me: Leave the cup overnight in sunflower oil or similar. Reverse fit the cup, insert it into the shaft and leave it overnight. Correctly fit the cup and insert it onto the shaft. I always leave it another overnight, before using it. I hope this helps you fit the cup.
The reverse fit first to form the cup first, was good advice. I did that and it functioned, but I still made that funnel of a soda can to help insert it the right way. Thanks a lot guys. I understand now that it was for a reason that late models of the 111 stove used an o-ring on the pump rod. Much easier to fit a new o-ring than this complex ritual...
