I've rebuilt a lot of walbro, zama, and tillotson carbs; they are all similar. Note the positioning of the pump diaphragm and gasket, if they are reversed, it will open or close the fuel valve too much or too little. The kits come with the screen. Use lots of canned carb cleaner to remove the fuel residue on all the parts. Make sure the one-way check valve flaps seat on the carb body. Be clean. Have fun, Mike