Re: 2000 75hp mercury swivel bracket
I recently did this to a 2002 Merc. 40hp. It was a huge job. You have to basically disassemble the motor to individual components. Take lower unit completely off (might as well replace water pump while down there), remove powerhead (make sure you label each wire and throttle wires), take tube completely out, remove bottom seal and bushing, replace bushing and seal, replace top bushing, then reassemble.
To do all this took me several weeks since I had to order lifting eye, parts, and because I can only work on the motor/boat after work. You will need to order a new gasket for junction between powerhead and exhaust plate or whatever they call it.
I'm a lawyer and I was able to handle the job. I wouldn't call it terribly difficult, just time intensive and a lot of moving parts. Seloc manual was very helpful.
Good luck.