Resealed lower unit Johnson 25, still getting water in... where to start looking?

Just finished resealing the lower unit on my 1981 Johnson J25RCIM, and I was not successful. Ran in a tank for a while this afternoon and checked the fluid, came out looking like pea soup. Water is still getting in somewhere.

Two questions, here's the first: is there a good way to check where the leak might be coming from?

I did a half-assed pressure test with something I rigged up, but I couldn't tell if my pressure test rig was leaking pressure or the lower unit was, so it was inconclusive, except for this: The pressure ran up to 60psi, then started dropping, and gear oil started coming out the three holes in the side of the motor (see photo). This makes me think it was coming out around the impeller area, but... that's a guess. It could have run out somewhere else and flowed there, since I did the test with the lower unit laying on its side. I'm not really sure what those three holes are about other than for water drain. When the oil started coming out I knew that wasn't a good sign, and the water test proved it. I thought I could hear some hissing around that same area, too.

Second question: The only thing I can think of, aside from simply botching the job, is that there was an o-ring I couldn't find a use for that came in the seal kit. It fit around the prop bushing, but it was thicker than the one that came off, so I used the o-ring in the seal kit that was the same size as the one that came off. I tried to use the thicker one but is looked like it might be a bit too thick, so I took it off and put back on the thinner one. Did I miss a place for that thicker o-ring somewhere? Is there a part lacking an o-ring?

I'll get another kit and redo this but since I don't know what I did wrong the first time, I'm hoping I can learn enough to avoid my mistake.

Thanks for any guidance --

Harold

?---Let the oil sit for a day and see if water seperates out.-----You may be misled by air bubbles in the oil.----Or pressure test the gearcase to see if and where the leak is.

Edit.........

Let the oil sit all night and this is what it looks like this morning -- not seeing any water separating out, but it sure looks weird. I used a gear oil of the right type for this application (not branded for marine, but it was the kind that isn't supposed to foam up if it gets water exposure). Is this what gear oil looks like after its been run in the lower unit?

Let it sit and observe.-----Use proper oil and test run again.

Refilled lower unit with Mercury lower unit oil, ran for 15 minutes in a tank in forward and reverse, here's what came out (see photo with blue oil). I can't tell if this is watery oil or not. The previous gear oil I took out (green) hasn't separated into water and oil after two days. The fluid doesn't look like it did when I put it in (it wasn't as opaque as it is now), but don't know if that's what it looks like after getting stirred up in the gearcase. Thoughts?

Thanks --

Harold