Do yourself a favor and call DA get the part number for the carb, then go to the local mower shop and get a carb kit and change the diaphram gasket only. it`s easy four scews and five minute, regardless of how many gallons are through it . if it has been sitting for a little wile that gasket is shot! if the engine wont hold a tune i bet thats what it is the carb kit cost about 10 buck`s!