It's you water tube leaking. You have to remove the lower unit and while you're at it replace the water pump and grommet.
https://www.amazon.com/Evinrude-Johnson-Through-Impeller-Replaces/dp/B07BHTGQT3
I actually tried pex at first. The pex didn't work. It didn't seal well and the diameter wasn't as close as this Polaris tubing. It actually does shrink(polaris tubing) and seals well. I tested it first before I started.
I have that water pump setup with the grommets. I bought the engine and didn't think about checking the water flow. I installed the engine on the boat and finally noticed no water flow. I pulled the lower unit and discovered the water tubes severely damaged. So instead of using the grommets I...
I think dextron 3 is pretty universal. I would look up your boat and see the correct fluid. Also if you have 2 engines, make sure you use the same fluid. Per google reading.
