I was doing my annual service on the boat this weekend and removed and cleaned the internal anodes on the motor.
I dont know how many folks do their own service, but if you run in the salt at all, its worth checking them and cleaning.
I dont know if all outboards have them? I have a 4S Johnson (Suzuki) and have 4 on the motor, the owners handbook does not mention them at all, the shop service manual indicates two, I have found four so far.
I attached some pictures of where they are located on my motor and what they look like before and after cleaning with a wire wheel.
Locatiopns outlined in white, lower left is where one is removed.