I'm trying to replace the water pump base on my 2002 Mercury 30 hp 2 stroke. Its the part that seals water from entering the lower unit at the drive shaft under the water pump. I noticed the old one was badly corroded when I was replacing the water pump impellar and decided to be cautious and replace it. Its not threaded and just seats in the housing with an o-ring, but I've tried prying every which way and cant get it out. Now that its destroyed, I have to replace it but I still cant get it out. I've attached a picture of the replacement part. Any suggestions?