Does this look like normal gear lube? I drained it last fall when I winterized and put new in. Not sure if I might have a leak and what I should do this spring when I get it out of storage.
Did you drain it just after running ?-----Did you let the oil sit for a couple of days ?---Could be full of air too.----If you are worried then pressure test the gearcase.
Sorry, but I disagree! It does look a little contaminated to me. It should be a clear dark green or clear dark brown. You may not have a major leak but I think certainly some water is getting inside the gear case. Check the gaskets on the fill/drain plugs and be certain the plugs are very tight, check the prop shaft seal, and check the drive shaft seal under the water pump. Also check the shift rod seal.
That oil does not have alot of hours on it. I changed it mid/late season because I found some fishing line wrapped behind the prop. I'm not sure what goes into changing the seals. It's a 90 HP Johnson. J90PLEEB. I think it might be best just to take it in and have it resealed and change the water pump out. I'm not the original owner of the boat and have only run the motor pretty lightly for 1 full season and a month or so the year before.
Did you put the oil in a glass jar and let it sit for a few days ?--Did you drain it right after running the motor ?---Have the lower unit pressure tested.-Get a quote from your favourite shop for a reseal job.
Fill with new gear oil entire gear case, use it some days, weeks, drain it to check it out, if same bit contaminated go for a lower unit reseal, but that's me...
Just remember that if it's saltwater then it's a lot more critical to the bearings and gears than a little freshwater.....just a bit of saltwater in the gear case can turn everything black with corrosion.....not good!...