Captain, it seems we have problems! Darn it...

[MTboatguy]

Have been getting my Tohatsu M18C2 ready for spring and summer, so I go and pull it out of the test tank this morning and the lower unit is covered in black oil, which seems to be lower unit oil, not 2stroke oil, so it looks like a lower unit rebuild is in order!, if it isn't one thing it is another! Murphy is sure hanging out at my house this year!

 

[Sea Rider]

Gear oil should not be black, unless used for zillion hours, before dismantling lower unit, get rid of old oil, put new certified 90 grade gear oil in and see if it exits as before. You have an olde 18 HP model, main parts as gaskets, o'rings, seals don't last forever..

Happy Boating.

 

[MTboatguy]

Oh,

I know gaskets don't last for ever, I purchased this motor late in the season last year and other than running it, didn't really get a chance to go through it, so I had planed on changing the water pump impeller as well as changing the lower unit oil, now that I have cleaned it up, since I posted this, I don't know if it is lower unit oil, it may have been 2 stroke oil that was black from sitting a while in the gas tank. I am sure I will get it worked out.

It is just right now, I have my 9.8 merc sitting here that I have to put a new carb on(arrived yesterday) so I can sell it, and now this bump in the road. I don't think summer will be long enough this year to fix all of the jobs I have to get done!

 

[pvanv]

Might be unburned fuel/oil residue inside the exhaust housing. Not uncommon. After a thorough de-carboning (and cleaning while you have the LU down), that may go away.

 

[Jon Boat Jim]

Sounds like typical 2-cycle oily exhaust to me. It happens every Spring and Fall when I put my 18hp in the tank to get it ready for the season or to put it to bed in the fall.

 

[Sea Rider]

If you assume it's gear oil coming out prop, then you have water entering gear case in which case you could have already milky oil inside gear case. Having less or more amounts of unburned 2 stroke leftovers draining through priop will depend entirely on the fuel/oil ratio used.

Happy Boating