I am trying to change a grease zerk on my lower unit because the ball valve broke on it, causing it to leak grease. The zerk is right above the gear box. I cannot get it off without striping it. Is this zerk pressed in or threaded? Do I need to bring it in to change it?

I have changed mine once. Will change it again this week due to leaking grease. Should b able to unscrew it.

Hopefully it'll break loose and not break off for you. Don't worry about stripping it, if it does chanel-locks or vise grips will give ya more control of it anyway.