Yes, part 37 is it. There is a screen and check valve in there. You have to remove the flywheel to unscrew it from the tank.Hey fellas! I just acquired a automatic oiler remington and for the life of me I can't pinpoint exactly where the duckbill check valve is. I am leaning towards part #37 as to where it's located. I enclosed the ipl. Thanks and appreciation in advance.