Dave:

The shoes and their springs are in perfect shape.  However, I followed up on your earlier hint about the actuator possibly being bent up enough to catch.  Actually it (mostly the red plastic area around the actuator button) appeared to be bulging, so I simply filed it down sufficiently so the shoes were no longer snagging on it.  So now the problem is now resolved.  The old 221 is running perfectly.  And I didn't have to do anything with the engine.  Thanks for your help!

While we are on the subject of the 221, is yours gray like mine, and do you know if anyone makes a good model paint to match it?

Dave