[BlueAxela]

The previous owner did not tell me what weight/type of gear oil to use for the lower unit. Should I be using 70W90? I am thinking of using synethic gear oil like Royal Purple for my lower unit.

How about for lower units for any motor? I might be getting a 96 8HP Evinrude, what gear oil do I use in that one?

[rickdb1boat]

A high viscosity lube will work in both. A 80W-90 or a 75W-90 synthetic will work fine...

[Texasmark]

I guess by '78 the electric shifter was a thing of the past which required more like a hydraulic fluid (20w type stuff) to operate over temp.

Mark