Black liquid pooling under floorboards/at transom

[ill13]

As the title says, I have some nasty black liquid pooling at the rear of my Achilles, I am running a four stroke and fresh fuel, where is this stuff coming from? Is it exhaust hydrocarbons mixing with water/spray? It's really black, like shoe polish black and really makes the inside of the transom, the motor tiller/cowling and inside pontoons a mess...

...Any ideas?

 

[TOHATSU GURU]

Re: Black liquid pooling under floorboards/at transom

It could be ancient aliens or those unburned hydrocarbons. I hope it's the aliens(that would be the second most most interesting thing ever posted on iboats), but it's probably just the dino goo...And it is usually caused by oil winding up in the combustion chamber from turning the engine when taking it on and off the transom.

 

[ill13]

Re: Black liquid pooling under floorboards/at transom

So, how does this stuff end up in the boat, versus say, dripping out the exhaust leg? I mean the heads are outside of the boat, there's no visible oil leaks on the engine anywhere. I've recently had the wooden floor out and hosed down the whole interior, there's no oil inside the boat. Is there some kind of vacuum/aerodynamic science somehow pulling exhaust fumes down around the bottom of the boat?

Finally, is there a way to avoid this?

 

[TOHATSU GURU]

Re: Black liquid pooling under floorboards/at transom

I misunderstood...When you said pooling at the back of your boat I assumed you meant pooling at the back of your boat on the outside. There isn't anything that would cause oil to be inside your boat other than tilting the engine up and having waste oil drip from the front of the engine to the inside.