Water in lower gear case Stringer 800

[Ristin]

1984 OMC 3.8L stringer 800.
I bought the boat July 1st 2017. On June 28th 2017 the previous owner had the lower unit resealed due to water intrusion. At the end of the summer I found water in the lower unit so I drained it and left it empty for the winter. I did notice the fill plug gasket was the wrong type and the drain plug gasket was quite mangled so I replaced both with the proper OMC gaskets and filled the case with Hi-Perf Mercury drive oil. Had the boat in the water about 4 hours and found water in the lower unit again.
Looked back at the June 2017 repair invoice and the mechanic had noted they could find no reason for leakage but since it was apart they replaced the impeller and installed a new seal kit.
Any ideas why the drive might be leaking again so soon after a re-seal? I haven't hit anything with the prop and there isn't any fishing line wrapped around the shaft.
Thoughts, suggestions?

 

[southkogs]

Has the drive been pressure tested? There's a lot of reasons a drive can get water in it (my upper gear cases were a pain to keep water out of).

 

[Ristin]

Haven't pressure tested this year. That's next on my list
It was press/vac checked after the re-seal last summer and checked out OK.

 

[Scott Danforth]

i have had a bad waterpump drain the upper of gear lube. also, if there are wear grooves in the prop shaft or input shaft, it can act like a pump and only leak when running.

 

[Ristin]

How long does the oil & water take to separate? I never saw free water in the lower drive but the oil level was slightly above the fill hole and the first bit of oil to come out of the drain plug was kinda foamy white-ish green. I drained it on Friday and the oil has been sitting in the drain pan. I dumped the oil off the top and there's just a thin layer on the bottom of the drain pan of the white-ish green oil...
oh, i should take a picture....duh
The cut in half container is the drain pan I originally drained the oil into

 

[Ristin]

i have had a bad waterpump drain the upper of gear lube. also, if there are wear grooves in the prop shaft or input shaft, it can act like a pump and only leak when running.

So far the upper & intermediate have no water and the oil levels are at the proper level.

 

[Ristin]

Talked with the mechanic that worked on the drive last summer. Turns out he had resealed the upper case and not the lower. In an odd way that makes me feel better.
Going to have the local shop reseal the lower.