Nice engine, nice sunshine at the wall.
By taking off the connecting, you can trouble-shoot which wheel set is binding, if it is a wheel set. Maybe a bent armature shaft, not likely but maybe..The eccentric linkage, as you already know, must be in the correct position to eliminate any binding, should be a easy fix for you with your knowledge.Another problem I will have to look into is I always turn the armature when I get a new to me loco. I can get a full rotation of the drivers, but there are 2 spots that is hard to turn. Eyeballing the drivers they look fine. Maybe it is
the linkage. I will take all the rods off and see. Well that won't work. The wheels need to be connected. Maybe take the eccentric linkage loose. I really doubt the owner had the wheels off.
Tom, as you know the sun is different this time of year. It was sunny, but sun was on other side of loco instead of behind me. But I thought good enough to post.
Take a connecting rod off the centre driver on one side only and then rotate the armature to see if you have any binding still. This way you will determine which side the problem is. It may be that you have a slightly bent piston rod going into the steam chest that needs straightening as a starting point. With a connecting rod disconnected you can manually slide the piston rod in and out of the steam chest to see if it sticks at any point which will tell you if this is the problem side. Good luck!!I will take all the rods off and see. The wheels need to be connected. Maybe take the eccentric linkage loose.