found a very small amount of water in LU

[zippy83]

Hi All,

I recently drained my LU oil and the first this that came out is a very small amount of water. I would say less than 10ML (0.33814oz) and after that it was dirty oil. I took a picture of all the oil that came out. This is on a 1974 Mercury 50HP outboard

Should I be concerned? If so what are my options? What should I look for?

Thank you
Zipp

 

[Texasmark]

Should not have water in the LU period. Water in a gear train causes rust if left unattended for long periods of time and under pressure it displaces lub oil which can lead to wear. In the winter a large enough quantity can burst your lower unit casting on a cold enough day.

Usually seals under the drain and vent screws are the culprits. If lots of hours or lots of years sitting up, you have 3 sets of seals....shift shaft, front of lower unit, drive shaft, under the water pump....comes out as part of the lower unit, and prop shaft...right in front of the thrust washer that the prop rides against.

A pressure test of 5 psig submerged in a tub of water will find your fault.....but first thing would be the screw gaskets then if that's not the low hanging fruit you can get involved in a repair.

 

[quicktach]

Be concerned. I agree with the drain and vent screw gaskets comment by Texasmark. Make sure to replace with the OEM gaskets. Clean the gasket seats first. Sometimes it can be economical to change oil more frequently than to pay a shop to tear down and rebuild - particularly on an older motor with lots of hours on it. But be careful what you decide to do.