Lower unit seals replacement on 96 force 120

[rhedayi]

Hi gang, when I changed my lower unit fluid initially, I noticed a very small amount of water in it. The oil in there was a bluish 90w oil. I did something dumb and used yellow 80-90w marine gear oil. So after about 6 hours at the lake on 2 occasions, I drained the oil and found a mixture of green / yellow. This time I used Star trom 90w oil and again ran if a few hours. Drained again today and noticed it to be not clear, either milky or just weird mixture of different oils. What should I do next? Pressure test the unit ? try to swap the seals using the seal kit which I think is this

Sierra International 18-2626 Lower Unit Seal Kit , white​

 

[jerryjerry05]

Yes retest and if possible do a pressure and a vacuum test.
Some test ok under pressure then when get hot they can suck in water as the temp goes up and down.
Most times a pressure test and new seals can fix the problem and finding a vacuum pump can be expensive.

 

[rhedayi]

Jerry. Thanks for the reply. I appreciate it. I definitely don’t mind getting my hands dirty and have many common tools. Is this something i could do myself and is there any tutorials you’re aware of. I searched for force lower unit. I didn’t have much luck. I may need to search for Mercury lower unit as they are the same from what i gather. I have already done the impeller service. I should’ve replaced the seals at that time for the shaft going into the engine. Stupid me.

 

[jerryjerry05]

The 96 Force lower is basically a Mercury lower, just set up to use Force linkage.
Check U-tube for video's