Kajun:
Given the corrosion on the lower part of your engine bracket have you given any thought that you might be overheating due to salt build internally within the engine cooling jacket? I have used MST Flushclear
(
http://www.mstguardian.com/Treatment.htm and found it quite effective at removing salt build up.
It looks like the company is having some trouble with an employee patent issue, but they might still be selling the stuff? It is rather easy to do with the lower unit already off, just mix the stuff up, fill a pressurized 3 gallon bug sprayer and connect it to water pump tube in the midsection with a rubber plug and fill the engine cooling jacket, let stand for 15 minutes and salts all gone.
Kamikaze