Gray sludge coming from middle of prop

[TheCat1212]

Good morning. I have a 1986 25hp merc. Over the week end, after a very short run, I noticed a silvery, gray sludge leaking from THE MIDDLE of the prop. I had just de-carbonized the motor as well as just changed the lower unit gear oil. My first thought was a leaky screw in the lower unit or a seal behind the prop. Then I realized it was coming from the middle. When I removed the 1 hour old gear oil, I DID NOT see any water intrusion into the oil. Is it possible this is from the decarbonization? Or do I just NOT know what to look for. I drained the lube into a clear jar and zero water settled out of it. What else in the engine could cause this? Please!

 

[Bob_VT]

Re: Gray sludge coming from middle of prop

Do not panic! It is unburned 2 stroke oil from the exhaust mixed with water from the cooling. 100% common and normal

 

[TheCat1212]

Re: Gray sludge coming from middle of prop

thank you for that. BTW, what does it look like when water is in the lower unit? i know when you pull the plug, the water comes out first. if it's been sitting does that mean it's pretty obvious? thanks in advance

 

[coolbri70]

Re: Gray sludge coming from middle of prop

yes the water will be at the bottom, so it comes out first, wanted to mention also, I had a tantrum, pulled the boat around back, and told the wife thered be no boating this season, I think I threw some things and cursed a lot :mad-new: then someone on here told me it was normal, oil from the exhaust:embarassed: upset over nothing

 

[joed]

Re: Gray sludge coming from middle of prop

Lower unit water intrusion will cause the oil to look milky as the water is mixed with the oil. If it sits for a long time the water might separate out and come out first from the lower hole.