Glenn, I just checked -- the camera has been sitting for 2-3 days since I last picked it up, and was NOT cocked. I cocked it, and fired, with shutter set to 500 -- and it took most of 1/2 second to eeeeease open, and then leisurely close, that first time (house is about 68-70 F with the A/C running). Second shot was perfectly normal.
Yes, it's a leaf shutter -- this is a fixed-lens RF camera, no reason for a focal plane. There's no brand on the shutter other than Petri, and I haven't had enough shutters open to be able to say "yes, it looks like a Prontor inside" or "no, this is a Seikosha copy" or "silly, this camera has a unique design."
For springs, my understanding has been that unless the spring is overstressed in design, modern materials don't weaken. Mainsprings in guns used to weaken over time (some of the earliest versions of the Colt 1911 had this problem -- if carried "cocked and locked" for a few years, they might start to misfire because the hammer wouldn't strike the firing pin hard enough), but they didn't recover when left untensioned for a while. If you bend a spring beyond its elastic limits, that's another story, but at anything resembling normal temperatures, a modern steel spring won't creep, weaken, or take a permanent set within its designed range of movement. I'll continue to leave my Speed Graphic at T and tension 1, because who knows what the steel was like in 1939, but I don't worry much about my post-War shutters -- and this is the only one I have (in current service, anyway) that cocks when I advance, other than my Spotmatic, and both of those are new enough designs it shouldn't be a problem.
Gunk it is, then. Ideally, I'd like to completely remove the shutter from the camera and clean it, then, but alternately, if I can find some money, I'd be willing to pay something to get someone else to do it. I pretty well have to work in "single sitting" mode, because my work space is the same table I eat meals at, so I can't leave a camera spread out in pieces while I think about stuff or soak parts or whatever.
Question is, how do I get the shutter completely off this camera? I presume I'll need to remove the front bits like I did last time, including unsoldering the meter wires, and then use a "special spanner", according to the manual, to remove the retaining ring from inside the back -- with very little clearance, and hardly any room to work, without scratching up the rear lens.
Dean, if you're interested in a CLA job, PM me...