These Kids are incredible. Ages at the time of recording
Naces 16 - Bass and Keyboards
Neisha 14 - Lead Guitar
Stacey 12 - Vocals and Rhythm Guitar
Ice 11 - Drums
You post asking about cracks in the Gel, when told to walk away you reveal you are buying it regardless. There are plenty of Threads of transom replacement. I suggest you read them, before asking more questions
Good Luck
Looking at the Parts Listing for 2000, it appears there is only one 50hp Evinrude that year. It does show a Rectifier-Regulator. Maybe because it is a Fuel Injected Motor.
Unless it is a Regulated Charging System, and back then, a lot of Outboards had Unregulated Systems, I wouldn't recommend any Battery other than a Flooded Wet Cell.
If one cylinder is bad on your Engine, I doubt the Oil System is the Problem. It is not Oil Injection, it is a System where Oil is added to the Gas before it gets to the Carbs, so all Cylinders would be Oil Starved and Damaged
Some will Insist that the Oil is Injected into the Gas, so, Oil...