I have a 1990 Yamaha 70hp outboard and it's leaking a black oily substance at the prop. It looks like maybe oil from somewhere mixing with carbon maybe. I changed the lower end unit oil and all was real clean. I didn't unhook the gas line over the winter as I forgot, but it seems last year it may have started to leak around there. I smelled it and it doesn't smell like gas or have the blue tint from 2 stroke oil either. Any ideas? Thanks in advance.
was the gearcase low on oil when you drained it?it sounds to me like its just residue running out the exhaust.. old fuel perhaps mixed with carbon from the exhaust...It wouldn't look like 2stroke oil once it has been through your motor and mixed with the cr@p in your exhaust..if your lower unit was not low on oil, and it wasn't a white creamy color, then your probably fine..regardsFrank
Thanks Frank, the lower unit oil looked fine, no milky color or anything. This oil is coming out down near the prop, in between the prop and housing meet and running down the very bottom fin. It's black but a funny black though, like carbon in it maybe, I hope it's just from the 2 stroke oil running out through the engine if it's possible for that. I didn't know if maybe there was a seal that was going around the prop and didn't want to run into trouble seizing something up and polluting the water. Should I run it in a 55 gallon drum to clean it out before going out on the water? Should it always do this or is it from sitting all winter? Thanks again, Dale.
Did you ever get an answer? In looking at other posts, it sounds like when we mix oil by hand that we may get some of this; sometimes. I have the same concern now. I had water drain as well (once I pulled the prop).
I think we both need to look at our gear lube to be sure it is not creamy.
70hp Yamaha oil leak at prop
Re: 70hp Yamaha oil leak at prop
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