This helped a bunch. I hadn't taken off that tip with the wrench Since I bought the darn thing. There was a giant Gray blob of goo clogging in there. Once I got that thing out the whole airbrush works much better. Thank you I also discovered that if you put a little bit of Vaseline on that tiny piston that your airbrush is a lot less likely to get stuck in the spray position. Access a little bit of lubricant between that piston and the internal O ring where the air feeds. Hope that helps.
I found this very helpful with my 2nd attempt at stripping down my HP C Plus (I may have used your short one on the first attempt a while back...). I think it would worthwhile covering common problems and how to resolve them. I have spent all night and this morning trying to work out how to resolve a clogged and jammed needle in mine. This vid helped me understand how it should be removed, but I had to trawl google to get advice on how to actually get the needle out...
You're lucky because that blue crap will dry out and gum up your tool, get some Badger "Neddle Juice" instead or simply use ordinary glycerine! - You can google "dons airbrushing tips" (a google site) and see for yourself.. 😉