Black stuff on prop

[rglos]

Maybe someone can tell me what this is. I just had the engine overhauled about 10 hours ago. O 235 L2C

I came back from flying Sunday with some very sooty black spatters on the prop. I didn't think much about it at the time and didn't have a rag so I went back yesterday to clean it off.

Then the surprise. The black would not rub off with solvent or avgas. It was almost like it was imbeded in the surface. So I took a pocketknife and started scraping. Some came off real easy and some not so easy.

My exhaust comes out of the cowl and points directly toward the prop.  It was a warm day and I am still running the engine full rich.

The spatter covers an area about 8 inches along each blade. The spread is even or about what you would expect from the prop hitting small droplets of pitch black paint.  I'm sure they have come out of the exhaust but I cannot imagine from what.

Has anyone seen this or something similar?

[Hmanvel]

It sounds like lead, maybe mixed with the remains of rebuild oil or something.  But lead is really hard to remove from your prop with any sort of solvent.  I normally see a gray/black spattering due to lead, but my prop is black so maybe some of it blends in.  Try using one of the cleaners made for glass cooktop stoves.  Harry Manvel.