mysterious exhaust smoke

[realcaptron]

Folks, on my older raw water cooled 454's, they have been running great and still so but.......last weekend when putting around about 1500 rpms, I noticed a never before seen darkish brownish grayish smoke coming out of starboard exhaust pipe, with still good water flow and all gages normal. Temp was reading 140ish and I verified that with ir. The engine appeared to be running smoothly. but I was worried about it and returned to the dock. But before I got to the dock, all exhaust was smoke-free again and at the slip, I could not get the smoke to reappear with increased rpms in neutral. I checked the oil and it looks primo and level is good. What was that darkish smoke?

 

[johnnygjr]

Pull some plugs on that smoker, Are they carbon fouled?

 

[willow]

Sounds like you may have run through some surface oil/pollutant on/in the water

 

[realcaptron]

Sounds like you may have run through some surface oil/pollutant on/in the water

That's an interesting theory, but my raw water intakes are only about 8" apart. Only one engine spit the weird smoke. I will check the plugs as Johnny suggested , and scratching my head at what else it could be. It occurs to me that the seawater enters a trans/v-drive cooler before proceeding to engine, and could it be that the cooler failed internally and mixed with trans or v drive fluid, but if that was the case, the smoke would not have cleared up, right? Or could the carb have momentarily dumped a bunch of fuel down there that couldn't burn and was expelled? It was not a pretty smoke. It wasn't black like you might see on a diesel, but it was brownish. And went away.

 

[makomark]

maybe some of that infamous pacific algae that grows out there?????

I can't say I've ever seen the tint you described.....and excess fuel almost always yields black....

 

[sandkicker]

..... after all the oil in the v drive is replaced with sea water, no more smoke!!!!