Cause of this milky water

[tomconnolly]

I am in process of replacing exhaust cover gaskets on Mercury L6 1988 to stop water in bottom cylinder problem. The powerhead came off pretty easily, but I find this at the drive shaft-see photo. Is it from the powerhead or could it be from the water pump or elsewhere? I'm guessing from the water and fuel mixed unburned in the bottom cylinder where I found the water leak.

 

[Chris1956]

It looks like fuel and water mixed. Your exhaust extension does have cooling water, exhaust and exhaust+ water in those three cavities, respectively. They could easily migrate to the driveshaft. If also could be leaking from the lower cylinder, past the seals you will be replacing.

When replacing the crank seals, make sure there are no grooves in the crank. If there are (likely) try to orient the seals to avoid contacting them. See if you can install 3 seals.

 

[tomconnolly]

It looks like fuel and water mixed. Your exhaust extension does have cooling water, exhaust and exhaust+ water in those three cavities, respectively. They could easily migrate to the driveshaft. If also could be leaking from the lower cylinder, past the seals you will be replacing.

When replacing the crank seals, make sure there are no grooves in the crank. If there are (likely) try to orient the seals to avoid contacting them. See if you can install 3 seals.

I don't have the crank cover off just exhaust cover and powerhead off lu. Does that milky around drive shaft look like symptom of bad drive shaft seal, or should I replace upper seal on driveshaft anyway while I'm in here?

Initially trying to determine if the milk is coming from powerhead or lu...

 

[racerone]

Your 2 stroke motor continually changes it's own oil.----Runs with clean oil all the time.----Some oil and gas goes right through the motor an never does anything.----This is what you are seeing.----And it is common on 2 stroke outboards.-----Lower unit oil does not get near that area.----Note------Outboard motors are fairly special machines.-----That is why most folks are mystified when looking at them !

 

[Chris1956]

Upper driveshaft seal is pretty easy to replace, since you just need to pull the flywheel to get at it. Do it whenever convenient. Also, if they leak, water does not get into the motor, just some extra air.

It is real smart to replace the lower crankshaft seals, while you have the powerhead off.