Re: 96 130HP Evinrude Gearbox
The number 1 spot for water intrusion into the lower unit is the drain and vent screw gaskets. They should be changed every time the screws are out. I would try changing them, along with a good synthetic oil, running it, then checking it again for water. If that doesnt solve the problem, you will need to pressure test it, or simply change out all the seals.
To pressure/vacuum test a lower unit:
a) drain the gear oil
b) use an appropriate adapter with a gauge tee'd in to apply pressure or vacuum. No more than 15 psig for pressure. You can use a bicycle pump or any other compressed air source for pressure. For vacuum, you need a vacuum pump.
c) LU should retain some pressure or vacuum for 45 minutes minimum.
d) If pressure doesn't hold, submerge LU in water to find leak source, or spray it with soapy water [possibilities: drive shaft seal, prop shaft seal(s) (usually two), shift shaft seal and the fill/drain screw washers.]
e) replace offending seal(s) as required.
Could you post pics ??
