1999 75HP Force/Mercury Odd Lower Unit Oil Residue

[pshelfo]

I have a 1999 75HP Force outboard which is really a Mercury. I drained the lower unit oil and found a weird golden color sheen that rose to the top of the pan which drizzle out and stayed on top. The bulk of the oil is dark blue/black but this golden stuff appeared to mixed in which is very odd. Not sure what this could be and sent a picture if anyone can help.

 

[racerone]

It is marketed by Mercury.-----It sure is not a Mercury !!------Was motor run shortly before draining the oil ?

 

[pshelfo]

It is marketed by Mercury.-----It sure is not a Mercury !!------Was motor run shortly before draining the oil ?

Thanks for the reply. No the boat has been sitting for about a month and was not run before draining the fluid. I do have some sort of fuel leak near the carbs and when I pull the boat out of the water I notice that a little bit of fuel is running down the side of the motor under the cowl. Not sure if a fuel leak inside the cowl could run into the lower unit.

 

[QBhoy]

Was there anything on the magnetic drain screw ? If it has one ?

 

[Chris1956]

Was it ever run, after the gear oil was replaced? if not, it is possible that you have two colors of gear oil, residual gear oil from the last draining, and the new stuff. Just a guess.

 

[merc850]

Fuel shouldn't run into LU [if it did water would too]; but you should fix it to avoid a possible fire!

 

[Ed27518]

I'm thinking either one of Four things, one is that there are two types of gear oil mixing(likely), I have seen weird colors when this happened on my motors. Another option is that there is a small amount of water getting in the gearcase (possible). Another is that something got into the lower unit and got ground up(not likely). Another(least likely) other option is some type of metal shaving or some failing component ground up in the lower unit.

It should not be fuel because if fuel was somehow getting into the unit then lots of water would get into their and you would notice it. If you want to make sure the unit is okay then run the motor for a little in a bucket on or on the water, and then check it again and if it looks good or just has a little stuff mixed in like the picture then you are probably fine and just check again after a couple weeks of use. if you see a ton of milky color after running it then you need new seals, and if the unit is clunky in gear or seems really weird then maybe some component failed.