I'm no expert, but i think 8 wks a bit early! Let the dog get used to it's name... see if it responds when you say "butch" or whatever... then start putting the leash on him for short periods of time... after he can tolerate the leash a bit, put it on him and start with the "come" command.

Each dog is different and can tolerate training at different stages. Most likely, you just got this dog... let him get used to his new surroundings for at least a week or two before you start putting the leash on him and stressing him out right away?

Have you read any training books? What kind of dog do you have?