I blew it out hard. After the diaphragms sat out overnight, they seem dry/brittle, so I'll just replace it (may have lucked out and found one locally, gotta call tomorrow). I was able to confirm it is a C3 EL42. Muffler is en route. Makes no sense having a cat on a saw, but I see new ones that are electronic/EFI. I'm going backwards with technology at this point, less computer is better in my book.Yep, the compressed air may well have (but may not have- depending on how liberal you were with it) screwed up the internal galleries.
New genuine off the shelf Zama's are not bank breakers and it might be a wise buy- A: you can swap your carb for a known good one for near the price of a repair kit- and B: You then have a spare carb for upgrading a Husqvarna 350 if you ever find one to build.
If it is a "green cap" saw, you might want to get an old style non cat muffler for it as well.
So, pressure and vac the powerhead if you have the means to do so. (getting some age on it now and might have a leak somewhere). New Zama (genuine not a cheap flea bay copy) with the limiter caps removed. New muffler (can be cheap aftermarket) and see where that gets you.