I did a search and found some pretty old threads regarding this subject, so I thought it might be time to start a new one.

I have flown about 200 hrs in my '61 250 in the last 18 months since I bought it. It has about 250 hrs on a new McCauley 3 blade the previous owner installed. Today, about halfway through a 3 hr flight, I noticed a few small specks on the the right side of the windscreen. I watched them very closely and they did not increase in number or size. After landing, there was a very small amount of what I beleive to be grease on the right side of the cowl just behind and outboard of the spinner. No streaks or other indications I could find. There was no obvious place I could see where it was coming from. Since it was about 25 deg F when I landed, I didn't get into an indepth fact hunting mission. OAT was between 0 and 10 deg C the entire flight. I was cruising at 2400 RPM, 65% power setting, at 6.5K. This is the first time I have seen anything leaking from the prop.

1. Is this an immediate safety concern? Do I need to find an A&P to take a look or can I take it back home (3hrs), and have my A&P look at it?
2. When I do start fact finding, are there specific things I need to look at.
3. I finished an extensive owner assisted annual in October. We had the spinner off, I did not notice any grease fittings on the McCauley hub. Did I just overlook them? My A&P that is VERY thourough did not mention anything about greasing the prop. If she greased it, I didn't know about it.

Thanks in advance for the advice

Jim

Hi Jim,

I doubt the problem is the prop. Have the AP check the front crankshaft seal. I know, hard to believe oil can go up stream then back onto the windscreen but its happened to me twice.

Good luck, Don

Jim,
The grease/oil in the Mac hub is dyed RED. If there is brown grease/oil residue on the cowl, then it is not from the prop hub. It may be from the crank flange/prop interface, or more probably is a forward crank seal as mentioned above. This is probably not an immediate concern, but you certainly should at least figure out where it is coming from as something has changed.
-Zach

Thanks Don and Zach!

It was definitely brown and did not have any red tint to it. Since it is probably oil, it is surprising to me the consistancy that it had. I gues that lends more creedence to the discussions about preheating your engine!

I'll get it home on Wed and see what my A&P and I can turn up. Getting ready to redo the panel, if a new crank seal is required, may be a good excuse to start the panel as well. I've got a feeling that will be awhole thread on it's own.

Jim

Jim,

As I recall replacement of the nose crank seal is no big deal. Have to remove the prop to do it.

Well,
Cleaned it up real good. Flew 3.0 home. No Oil leak. Guess I'll just continue to watch it real close! Thanks for all the input.

Jim