Water in gearbox oil

[Kochi]

Just changed the gearbox oil in my Mariner 3.5hp 4 stroke outboard and the old oil was milky. How could water be getting in and how do I fix it?

 

[VicS]

Most likely place is through the propshaft seal which is easily damaged by fishing line etc

second most likely place is the vertical drive shaft seal

could also be via the drain and level plug seals ( it's recommended that they are not reused but they always are. Some would put this at the top of the list))


Change the water pump impeller at the same time if its not been changed recently

Two diagrams that might be helpful

http://www.boats.net/parts/search/M.../Gear Housing Assembly, Driveshaft/parts.html

http://www.boats.net/parts/search/M... Housing Assembly, Propeller Shaft/parts.html

 

[Kochi]

Thank you VicS. Year 2010 and model number 7F03201ZK

 

[VicS]

Oh, I cannot find that model number.

If the diagrams I added don't match what you have I cant help.

The trouble is all the info is on American sites and they only list models that were built or imported into the USA.

 

[VicS]

I have now but listed as a 2006 model

That looks the same as the diagrams already posted

 

[Kochi]

Thank you again VicS.

There's no fishing line anywhere but I felt when I undid the level plug that it wasn't particularly tight so I guess before I go much further I'll use it a few times then drain it again and see if there's water in the oil.