A friend gave me the lawn mower. It didn't have a primer button so would start it by spraying some gas in the carb. It didn't work he took it apart and now I can't get it back together:(

Can't get what back together, the carb, or the primer bulb? Or what? Need more info to be able to help you.

Go to www3.sears.com with the model number and print out the parts breakdown. It might take two passes, one to get the engine model from the model #. I had to do a select all, copy and paste into a word document to do it.

Take a picture of the "puzzle". Post it.