"Soot" from exhaust

[Paul65]

My A4 seems to be running great; correct oil pressure, engine temperature, amp output, etc. However, in the past month I have started to notice what looks to be soot floating on the water than appears to be from my exhaust. I do not notice any smoke coming from the exhaust, just this slight trail of soot showing up in my wake. Other than the obvious pollution concern, I am sure the slip-neighboring skippers would like to avoid having a ring of soot start forming on their waterlines.

My first (actually only) guess is that I'm running a bit too rich. But, before I adjust anything, I would really appreciate the input of others, especially Don's. Any trouble-shooting tips?

Paul

[Don Moyer]

Paul,

In cases where an engine that is in otherwise good operating condition begins to spew a bit of oily soot out onto the surface of the water, we make the assumption that it's coming from the water lift muffler. Water lift mufflers tend to collect quite a bunch of "combustion debris" which will eventually start to come out with the exhaust.

You might follow the procedure in our manual for an acid flush. An acid flush is normally prompted by a need to clean out the cooling passages within the engine, but I have always felt that the huge collection of crud that folks report coming out with the exhaust water when starting up after an acid flush was from the water lift muffler.

Regards,

Don

[Paul65]

Don:

My A4 was completely rebuilt in the spring of 2004, and the block was dipped before the motor was reassembled. Also, although my motor is raw-water cooled, I sail on Lake Ontario only. So, as you suggest, the water lift muffler seems like a very likely culprit. I'll check and flush it.

Thanks again for the advice.

Paul