I am replacing the water pump on a 4 HP Evinrude. I believe the year is about 1969. It's a direct drive. You can see the lower unit below. Of the two screws holding the impeller casing down, one came out easily. the other was missing the head. With one screw out and one missing the head, the impeller casing should lift off but mine is stubborn. I don't see a slot to pry it. Should I grad within the slots by the drive shaft and attempt to pull it? Any tricks to remove this stubborn component. I don't think I need to easy out the broken screw to get this cover off. Buster7 
