I will be happy to assist you. If you have a question or need clarification please post back at any time.
You can order parts from your local Evinrude dealer or a great online site is www.boats.net they sell OEM parts at discount.
I am assuming you are referring to the seals in the trim cylinder. Here is a breakdown of the trim unit.
If you are changing the seals around the trim cylinder you will need a spanner wrench. You can find one at most good auto parts stores. The top of the trim rod is held to the midsection by a large stainless steel pin. You need to remove the cotter pin holding it in place on the port side, then pull using a puller. If the pin has corrosion on it the pin may be frozen and you may be better taking the engine to a qualified shop. Hopefully you are in fresh water!
I've had to grind and drill out the pin which is difficult.
If your leaking is around the base of the trim motor #39, then that is a single O ring #34.
To remove the trim motor you will need to remove the engine from the boat to reach the back screws. When you replace the screws use some gasket maker on the screws. I would recommend replacing the Phillips head screws with a 3/8" head machine screw.
Let me know if you need additional information on this.