Fouled plugs

[moparcanuck]

OK, my stock 440 Six Pack with electronic ignition was missing badly under load. On advice received on the forum, I changed the plugs and now it runs like a brand new one.

The conundrum is that the 4 plugs at the front of the motor were black with carbon. The rear 4 plugs were a nice brown. I have no idea why.

After a few days of normal driving, if I punch it, there's a trail of black smoke out the back. After that, no more black smoke when I punch it.

Ideas?

 

[Badvert65]

Any chance the front carb is flooding or leaking fuel?

 

[nm9stheham]

If you are getting black smoke after running normal for a while and then it clears up after some hard running, you are 'burning the carbon out'. It is likely accumulating in the cylinders and exhausts. This is likely due to the carb running too rich in some phase of engine operation. That would explain the carbon fouled plugs you took out. Are you running a single plane manifold? Carb make and model please?

 

[D575]

I had an issue with fouled plugs, I know I'm jetted a bit rich and need to go up with the power valve . the choke sent it over the edge. I wired the choke open and no more problems. when I get around to it it I'll change the power valve.

 

[moparcanuck]

My choke is wired open as well. The carbs are standard Holley Six pack carbs.

 

[nm9stheham]

Any chance the carbs have been swapped around and the jets/orifices are wrong now with a center carb on one end, etc? My first thought is that one carb is off tune, and this might be the cause. The 2nd post refers to the front carb being off and a carb swap could do it.

Some info on the carb to carb differences: http://www.mopar1.us/6barreltips.html