Thanks for all your replies.
The parts are new and genuine OMC parts.
I am doing this as a preventive/maintenance percussion.
It sounds like there is not much to it and I will get a couple of
friends to help me. They have some experience in the area as they have
had boats for years.

What about flushing kits, What are your experiences as to how the
easiest way to flush with after use?
Jens-Erik