Outboard - Oil coming out of exhaust.
Hi, wonder if anyone can help. I have a 4hp Mariner outboard, I'm not sure of its age but would think it was manufactured in the mid 90's. I used it at the weekend to power my tender and then took it back home having laid it down in the car. When I got it out of the car it discharged some thin black oil, not much but its the first time it has done this. I then noticed I had forgotten to switch off the fuel supply so I set up a tank and fired it up. Normally it starts first time but seemed to be flooded. This cleared ok and it ran fine.
Can anyone help and tell me where the oil might of came from? Aside from the gearbox does a simple outboard like this have any other places where oil may of come from?
You'll get a mixture of oil and petrol seeping out of the carb if you haven't run it dry before laying the engine down - more so if you haven't turned the fuel off.
Also, you could get the occasional oily dribble out of the exhaust on the leg.
Gear oil is (really) thick & sticky.
You are probably using 50:1 mixture of petrol/oil, and as misterg suggests, it is probably the oil out of the fuel, after the petrol has evaporated. Sometimes is drips into the engine cover, and you find oil residue inside. Sometimes out of the exhaust when the engine has not been run up to temperature to burn off the oil.
Its happened with my Evinrude twin 4 when I have forgotten to turn the fuel off when tilted on the dinghy. I return with a wet patch of oil on the dinghy floor.
Not at all uncommon... normal in fact ... for some black oily residue to drain from a 2 stroke outboard. Its just partly burnt oil from the fuel.
In your case some leaking petrol has probably flushed it out.
Be aware that leaking gear oil would indicate a leaking gearbox oil seal which would almost certainly allow water to enter. ( except of course in the case of Seagulls which leak gear oil anyway and run with a mix of oil and water in the gears)
See THIS ITEM from the iBoats forums
Thanks for the replies, it all makes sense now, cheers.