Black oil leaking through weep hole in lower unit

[bnetzky]

I took the my 1977 75hp Chrysler outboard out for a test run yesterday. I noticed this morning there was a small pool of black oil on my garage floor, which was leaking from the weep hole on the lower unit.

I suspected that it might be gear case oil so I cracked the fill screw but the oil was much lighter in color (brown/tan) than what was on the garage floor and I did not notice any water come out when I opened the screw either, which I assumed I would see if there was a leak.

Any ideas what the problem could be? Could this be two stroke oil? If so, why would there be so much leaking out the weep hole?

 

[Jiggz]

This is almost natural depending how rich of fuel air mixture gets into the cylinder and worst yet, how long you keep the engine at idle speed. The black oil is actually unburned fuel from the cylinders which failed to get collected by the fuel recovery system. To prevent this, make sure you keep idling at a minimum.

 

[MickLovin]

More than likely running too rich or one of your cylinders may not be firing correctly. Check the link and sync sticky to sync your carbies correctly. If it is running ok, may just need an adjustment on the carbies, other possibility is your fuel pump diaphragm may need replacing.