The other day a friend of mine told me brown smoke shot out of my exhaust when i took off a little hard. I told him if he was sure it was brown and not black and he said it was a golden brown color.

My car is running really rich,( burns my eyes after 3 mins of idling) and i believe its mostly due to an incorrect idle mixture. Im pretty sure my plugs are fouled by now so im gonna change them out today.


My questions are:

What does brown smoke mean?

What are the effects of fouled plugs?

Could a fouled plug cause an even richer mixture?

My car has been smoking a lot more than usual at idle and it doesnt smell like oil. It smells like fuel. Could a rich air fuel ratio cause any smoke at idle?

Its so bad that if i leave the car idling next to a curb the exhaust will stain the curb black ( has side exhaust pipes)

What are a good set of plugs to run? I usually just stick with ac delco coppers, should i stick with the stock gap?

Any tips on setting idle mixture? Some people say to go by idle speed and others say to listen for idle quality. Am i supposed to tune one screw at a time or do one turn on one side and then one on the other side?


My set up is a carbed mild 305.


Thanks for reading guys, i appreciate any input even if u can only answer one of my questions. It helps.

 

You're probably blowing more unburned material out the tailpipe than you're burning in the chamber.

Misfiring, detonation...

Yes on an FI car.

Yes

Stock plugs, stock gap

Set both sides equally to just slightly leaner of the point that gives you the highes vacuum at your idle speed, after you've already set up your ignition curve.

 

Thanks apeiron, im gonna start with new plugs and work on getting proprer mixture.