Lower Unit Issue

Hi All,

I have a 1975 70 HP Evinrude, I just recently bought it and checked the lower unit fluids and noticed that it was a brownish/milky color. The person I bought it from said he just replaced the lower unit fluid last fall. I have inspected the lower unit completly and see no visible cracks anywhere on it. Can anyone explain how water would be getting into the lower unit to cause this problem? Thanks in advance for any help!

Re: Lower Unit Issue

Drain the gear oil and test the LU.

Test leaking lower unit ? pressure or vacuum (both recommended)

1. Drain gear oil
2. Pressurize (or apply max vacuum possible) to no more than 15 psig with air (see OEM shop manual for max for your motor)
3. Submerge in water, look for bubbles
4. Turn or move every shaft with a seal
5. Possibilities
a. Drive shaft seal
b. Prop shaft seals
c. Shift rod seal
d. Cracked casting
e. Drain/fill screws/seals
6. Repair as needed

For V4 and V6 lower units, should hold some pressure or vacuum for at least 45 minutes.

If a seal(s) is found to be leaking, inspect the shaft (prop or drive) carefully for grooving. If there is any, make sure the new seal(s) do not seat in the same place as the groove.