running lean and engine damage

So how lean was it? You say it idles better. Was it just an external adjustment to the carb? Or did you change jets and/or metering rods?

If you adjusted the mixture screws on the outside of the carb, you really didn't change how rich/lean it was. You just added some air/fuel to the idle. Past 1/4 throttle the idle circuit has no effect on richness. Also, if the idle was lean it would run rough and stall long before any damage occurred (not much load at idle).