Thank you so much. It is clear to me now after the great pictures on
the site that I have a "pre-alpha" unit. I will check the serial
number to verify. Is there any reason to take off the entire stern
drive to replace the impeller or should I just take of the lower unit?
The only reason that I would take off the whole thing would be to
grease the U-joint. I am of two minds on whether I need to worry
about this. First, I have seen many posts where it is recommended to
grease the U-joints every year. This boat is new to me so I have no
idea when it has been done last. On the other hand, once a year seems
like overkill. How often does anybody grease the U-joints on their
car? I don't think my truck even has zerk fittings on the U-joints.
I only use the boat about 20-40 hours a year at the most. I am also
wary of openning a can of worms. What does MerCruiser say about
U-joint lubrication?

Chris