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...... and several that won't give consistent atomisation. Going back to the previous generation without the guided needle the one that worked best had the spring retained in a 2.4mm hole. As the bore of the spring was a close fit on the 1.4mm needle this acted as a guide. Now I have the guided needles a 'double' guide may be causing problems. I bored the spring seats out to 2.5 mm without obvious success The springs are quite a close fit on the needles so maybe that is causing some restrictions .......
Oh! next time you do that exciting 'flammenwerfer' test/ experiment, why not try a dark as well as the light coloured background. It may make the flame front, even more visible and exciting to watch.
By golly, does that thing actually run!?