Maybe I replied too quickly. The "play" I was experiencing was radial. If I took the front sprocket and tried to turn it forward and backward in the direction it turns, the play was that way (could be described as horizontal, but in the forward-backward way, not side to side horizontal). I just went to the old engine that I pulled out and wiggled the (less than 1000 km from new) sprocket. It is as I described but maybe two to three millimeters and almost no play if I try to twist it side to side (as Bob suggested to help it follow the chain). It is definitely NOT locked down tight. I think the new engine's sprocket is more the way it should be but I am fairly new to this. I do remember thinking that it was excessive, and I still do.