I ran accross this video and found it very interesting. I did not know exactly how all the parts functioned in the lower unit. I post it hoping some of you will find it as interesting.
You Tube Video of lower unit
http://www.youtube.com/watch?v=vuAcrDFvApA
You Tube Video of lower unit
http://www.youtube.com/watch?v=vuAcrDFvApA