Water in gear case oil

[reveregrady]

2011 Etec 200. Changed gear case oil before ‘23 season and at the end of season. At the end of season noticed slight “milk shake” gear case oil. Changed with fresh oil and put away for winter. Now, prepping boat for water. Lowered lower unit. Pressure and vacuum tested separately at 10-15 psi. While pressure testing I rotated prop shaft and moved shift linkage wile spraying water pump, prop, linkage, etc w/ soap water. No bubbles. Vacuum test held vac at 15psi for 10 min no problem. I replaced water pump in the previous season. Any ideas where water could be getting into the gear case?

 

[seasick]

Do a pressure test again using the soap water solution on all penetrations, drive shaft, shift shaft and prop shaft During the test, put a reasonable amount of pressure on the drive shaft, both side to side as well as up and down while rotating it. Look for bubbles
Do the same for the prop shaft; turn while putting side to side pressure. The shift shaft also should be wiggled to look for bubbles.
If the LU holds both pressure and vacuum you can probably exclude a problem with the LU housing such as a crack or a small pin hole due to electrolysis.

Also check that the fill and vent plugs were tight and the gaskets were good ( hard to tell sometimes).
When you checked the drive shaft for leaks was the water pump removed? In the photo it looks like the pump is installed. The seals for the drive shaft are under the pump assembly I think and if so and they leak, you wont see the leak with the pump housing installed.

 

[Hookup1]

Were the fill and drain plugs really tight?

 

[SkunkBoat]

did you replace the fill gaskets every time? They get a ring when you tighten them and then if you use them again the ring is in a different place.

 

[SkunkBoat]

was the water pump off when you bubble tested?. Gotta take it apart and spray on the seals.

 

[reveregrady]

Thanks everyone for the tips. I will take the housing off the pump and spray, I didn’t know you had to. I will also try wiggling the different areas. As for the seals on the plugs, no they were reused. They will have to be replaced.

 

[seasick]

Thanks everyone for the tips. I will take the housing off the pump and spray, I didn’t know you had to. I will also try wiggling the different areas. As for the seals on the plugs, no they were reused. They will have to be replaced.

in addition to being replaced the drain and fill 'holes' should be checked for residual pieces of the old washers.

 

[Fishtales]

Could be an issue under load that when static you don't observe.