Hey Guys,

Wondered if I needed to be concerned with the moisture and black soot coming out of the exhaust on my 77 when it idles.

400 engine with Hedman headers, Flomaster 40s - on their sides, dumped at the rear axle.

When I start it and warm it up in any weather, I end up with a black carbon and water puddle under each pipe. No blue or white smoke, just common exhaust fumes, both at high and low idle.

What's the deal???

 

Sounds like you're running rich. What kind of carburetor is this? If it's the factory Motorcraft 2-barrel, then it's possible the power valve (or gasket) is letting fuel seep past. Or, the mixture screws are set incorrectly. You should set the idle mixture with a vacuum gauge.

To answer your questions, no, it's not supposed to happen. As far as it hurting anything, probably not in the immediate future, but running over-rich can dirty up your spark plugs more easily, and coating the combustion chambers with carbon deposits over time can lead to carbon hot-spots, which leads to dieseling after the engine is shut off. And in any case, you'll need to fully understand the source of the issue before assessing the risks.

 

Thanks FMC, I installed an Edelbrock 600 carb and performer intake, MSD ignition. It did this before with the stock 2bbl setup, too.

 

Holy smoke..no pun intended..thats what exactly mine does too..plus it dieseling out also...so fixadjust carb? (holley 4bbl) replace exhaust gaskets? and most likely spark plugs?

 

You say when you start it up and let it warm up its doing this. So I suspect to much choke on warmup.