There are a number of Tecumseh carbs on Ebay for around $18. They are p/n 640025 and state they are universal and can fit many types of equipment. Can this carb substitute for the p/n 640172 carb I have on a Sears 4 hp Edger, model 143.994001? I am having problems with the carb after I rebuilt it and would prefer not to buy a new carb for $60+. Thanks.