As I'm eyeball-deep in new students I cannot devote my three remaining brain cells to figuring out the mechanics of an unfamiliar shutter, but I think Terry's on to it. In many leaf shutters that main ring acts as a cam to cock the shutter, and if it's not in place the shutter's not going to work,
What I can suggest is (once you get the shutter blades moving), rather than going straight to the nuclear option of total immersion shutter baptism, applying Ronsonol to the shutter blades generously, then shake on a little powdered graphite and work the shutter several times. Clean with Q-tips, blow off, and see where you are. If it's not right do it again. The solvent helps to carry the graphite into the blade pivots and may help you avoid full disassembly. Obviously, if the problem lies elsewhere you'll have to address it, but the shutter blades are the most likely culprit in my experience.
Also, I should note that I've use Ronsonol to clean lenses - yes, the glass - on numerous occasions with no ill effects. I'm not saying there aren't coatings out there that might dissolve immediately, but so far I haven't encountered them.