Jan, I can see a Zippo shortage developing in Denmark shortly!!!
Great fun!
Just curious what Zippo/oil ratio you are using? Everyone seems to have a favorite and they are all over the board. I WAS using 5:1 Zippo to Marvel Mystery Oil. Just cut back oil content, as it seemed a lot of oil was accumulating around the open piston end of cylinder. Seems to run fine on 10:1 ratio of Zippo/Marvel Mystery Oil with less oil buildup which I assume is better for spark plug too.
Wish there was a bit of science behind these various mixtures !!!!
Rog