Tom, Maybe I am misunderstanding the type of blues you have 
, but, in order for the train to keep running the balance assembly has to be put in, without the balance the escapement will lock up as your describing, it will not keep running. You can manually move the lever to check the lock, inside and outside shake, run to banking, ect…before putting the balance in, the lever should lock and run up the jewel a bit to banking and stay there unless you manually move it to the other side. hope this makes sense, William
