Oil drain tube leak
My push boat for my barge had some oil in the bilge. After removing the console and engine I found no rusted oil pan, no split lines....everything looked surprisingly in good shape. The culprit was a coolant hose vibrating against the oil removal tube. Quick braze and a zip tie to keep the hose off of the line and good to go. Did get a good chance to clean bilge refresh the rtv on the pan and change oil and plugs. Don't forget to check the simple things. Ten hours down time and a lot of needed deck repairs was fun.