that small diaphram that you broke has something to do with the idle fuel metering i think im not sure someone quote me if im wrong .... i have rebuilt many walbro and zama carbs and by the looks of it you have a wjl c1u series carb and dont belive i have ever seen this part in any of the rebuild kits avaliable and you would require a special punch to install the brass clip... you could possibly just get a new carb off ebay for 40 bucs
