Disclaimer: I’m new the outboard game and am just learning a lot about trim/tilt myself, but based on the zero response I got on my trim/tilt question I’ll tell you what I know.
I have an 88 Evinrude 40hp, so things may be a bit different but there should be some sort of screw towards the middle of the motor. Once you unscrew that the old fluid will spill out. From there, you’ll need to work out how to get your new fluid into that hole. On my model the threading is identical to the lower unit oil screw so I am using the pump I got for that. They’re inexpensive. If that doesn’t look like it’ll work on your model, I’ve seen others use a little medicine syringe that you’d get for a baby. That’s gonna be slower. Once filled I believe you want to tilt up and down a few times to bleed out any excess air. I recommend you watch a video on a similar model as yours to get a feel for what needs to happen. Seems pretty foolproof for the most part but with these older components it’s probably best to do it right the first time.
Good luck.
