I'm working on a few older poulan saws (one is a micro xxv) and all of them need the check valve that screws in behind the clutch. It's used to pressurize the bar oil to push it out onto the bar, the part number is 530069142. Everywhere i looked said you can get them from sears.com or poulanpro.com. Well, i checked both of the sites and they say it's no longer available. So, does anyone know where i can get this check valve or are these saws just useless now? thanks for any help.