I have a 10 hs evinrude sportwin and I believe its year is 1959. There is a small hole on the bottom of the gear case behind the screen. Not sure if it is supposed to be there but it is slowly leaking a grey colored sludge like substance and it drips on the prop. I drained the gear oil and the gear oil was good. Not sure if it a problem, if it is what could it be? I can post pictures of the hole if it helps. But I don't have pictures of the sludge since I wiped it down when I drained the oil. Thanks for the help.