Lower unit lube turned to black sludge, WHY ?

[doctorwho]

Last year I rebuilt the lower unit on my 1962 Evinrude sportwin. I was surgically clean and cleaned the middle extension area as well. I then filled it with fresh lube and took it for a spin. It worked flawlessly. I put maybe 2 hours on it and parked it for the winter in my garage, fogged the cylinders and thats it. While getting it ready to use this year I again changed the lower unit lube and was stunned when it came out as black as tar and was almost "chunky" in texture.

The only thing I can think of, if it's even possible, was that the cylinders are all carboned up and over time the fogging oil leaked past the rings and somehow found it's way through the exhaust area all the way into the lower unit. I realize how bizzare that sounds, however, what could have caused the lube to go from a pristeen golden color to jet black sludge in that short a time?

I can't wait to hear all the laughs on this one.

 

[Joe Reeves]

Re: Lower unit lube turned to black sludge, WHY ?

It is next to impossible for the exhaust to enter the lower unit in the manner you speak of, at least in my career I have never encountered it.

If the lower unit lube was black in color previously, that color will take some time to be canceled out as it hangs onto every imaginable surface within the lower unit for a long time.

Years ago, a percentage of the HiVis gearlube was whale sperm oil, black as black can be, and really had a foul odor to it. If that unit contained that type mixture at one time, therein lies the explanation.

That whale sperm oil though, was always a mystery to me just how they ever got that whale to............ oh well, a mystery is a mystery.

 

[Mas]

Re: Lower unit lube turned to black sludge, WHY ?

Any chance of using the wrong lube oil?

MAS

 

[doctorwho]

Re: Lower unit lube turned to black sludge, WHY ?

The original gear lube was a golden color as well. When I rebuilt it I was very clean and left no trace of old sludge. I used 90 hypoid as indicated. I just can't find a reason for the drastic clange.

 

[11rufus11]

Re: Lower unit lube turned to black sludge, WHY ?

I would drop the lower unit and check for any damaged seals or anything out of the ordinary. Maybe something got chewed up in there and mixed with the lube. I never saw sludge develop after one season.

 

[F_R]

Re: Lower unit lube turned to black sludge, WHY ?

Aha! Somebody else remembers the whale oil!! Not many people even knew about that. That was inside knowledge. It isn't considered nice to kill whales for their oil anymore. But it was good lubricant.