I'm rebuilding a couple of SA200's.  They are both missing the short section of linkage that attaches the arm from the governor to the carb's throttle shaft.  (Marvel carbs) This is the piece that locks onto the throttle shaft.  One of them is also missing the governor arm assembly, but I think that's available new still.  I don't have clear pics of how this goes together (old TM179 manuals on the internet are poor copies picture-wise), but I have seen enough pics to at least know that I'm missing these parts.  You can email me at jinskeepATyahooDOTcom, or call 54zero828sixoh53.  When I have these parts, I will post back here that I no longer need them.  Thanks!