Poulan - - says you have a WT628 User Manuals | Poulan ... also says no rebuild kit.
So I suspect this is a trick question.
Welcome to walbro.com has the general service manuals here wem.walbro.com/distributors/servicemanuals/
Welcome to walbro.com also has http://wem.walbro.com/distributors/ServiceManuals/CarburetorGuide.PDF
there is a WT-628-1 with a rebuild kit, you will have to figure out if it will fit or not.
I have run into that before where is says no kits available for that model carb. I then go on ebay and wouldn't you know it, there is a kit for the carb. They always have pictures of the diaphragm and of the gaskets so that you can compare and make sure the kit is correct.