1957 Evinrude 10 Lower Unit Black Sludge

[duckbuster61]

My 57 Evinrude 10 hp has a small hole just above the center of the prop. After I run it, black grease runs out. Is that lower unit grease or leftover oil from the fuel? I've read on this forum that there's a weep hole somewhere is that what this is? My 7.5 and 3 don't have it. If it's a weep hole, what's it for?
Thanks

 

[1946Zephyr]

Re: 1957 Evinrude 10 Lower Unit Black Sludge

Yes, black seapage like that is common. It is unburned oil from the crank case. If you have weep holes, make sure they stay clean and nothing plugs them up, because water can sit in there, in the winter and freeze.

 

[duckbuster61]

Re: 1957 Evinrude 10 Lower Unit Black Sludge

Thanks for the info. Still don't understand what that's for, but you gave me confidence to ignore it. I'd hate to mess up a great old motor.

 

[HighTrim]

Re: 1957 Evinrude 10 Lower Unit Black Sludge

If you have ever opened up a gearcase, you would see that it has cavities within the casting.

Now when your outboard shoots the spent cooling water out the exhaust, some fills these cavities and doesnt make it out of the exhaust port.

That is where the weep hole comes in. It sits at the lowest point of the cavity, to ensure that the gearcase drains completely. It it wasnt there, the water would freeze, expand over the winter and crack your gearcase.

As stated, when you have your gearcase off, always check that the weep holes are clear. I have seen many that are clogged and need to be bored out.