plugs fouling out

[peeweecollins]

my 318 has a miss in it I checked some of the plugs and they were all black and sooty so i'm assuming the truck is burning rich I tried adjusting the carb but couldn't tell the air from gas with those two little set screws on the carb I really don't know if thats even the problem I had one guy look at it and he said he wouldn't suggest adjusting because the truck idles fine but that only when its in park or neutral I would appreciate any suggestions thanks.

[DiverDwnPowrRam]

What year truck? What size and model carb?

[peeweecollins]

81 d 150 2 bbl holley.

[rolnblok]

There are several things that might be individually or combined to give you troubles here. Can you describe the plugs a little better? Are they black and "dry" sooty or "wet sooty? Is the timing set correctly? Are all the plug wires good? How about the cap and rotor? It sometimes can be difficult to sort out a carb issue if the ignition is not in peak condition. If the ignition system is good, then start looking at the carb. Is the choke staying closed too long? Is the choke stuck in a partially closed position after the engine warms up?

Has the carb been rebuilt recently (last 3-4 years)? If not, that might be a place to start.

If someone was monkying with the idle mixture screws, they could have set them a little rich and then adjusted the curb idle setting down to accommodate. Hard to say.


If it were me, I would make sure the ignition was in good condition. I would put a set of new plugs in. I would drive normally for a few days. Then pull EACH plug to evaluate what is going on in the motor. If all the plugs were dry and sooty, I would then suspect carb issues. If only a few plugs are sooty and "wet" and some are the appropriate tan color, then I would suspect an engine wear issue. If all are wet and sooty, then you could have a combination of issues going on.


If you want to ignore the above and start turning stuff on the carb, at the very least put the fresh plugs in to help evaluate if there are any improvements. Sometimes, once a plug fouls, it may never really work right after that. Again, make sure timing is right. If you do a search on this forum there are several posts that will guide you in the right direction to adjust your idle mixture screws. Some get you in the ball park. My preference is to use a vac. gauge to do this. Adjust the idle mixture screws (one at a time) to get the highest vacuum. Then double check your curb idle speed.

[Speed Dragon]

Dirty air filter? If you haven't already, do a complete tune up: plugs, wires, cap and rotor, fuel and air filters, set the timing to factory specs (if needed).

Also make sure the choke is fully open at normal operating temps. IS the truck actually missing or having driveability problems, or you just pulled the plugs to look at them? Also, what plugs are they? Don't use platinums.

[jrhd97]

What plugs work the best in these money pits?

[Speed Dragon]

Pretty much any regular, non-platinum plugs. Factory used Champion RN12YC, Autolites also work good. Dunno if they make plugs for the 318 or not, but NGK makes really good plugs as well, I use them in every import I work on and all my turbo Dodges.

Only thing I hate about using Champion and Autolite though is they are both made in China now :(

[DiverDwnPowrRam]

pssst...hey buddy....you do realize that this is a dodge lovers forum...right?

[jrhd97]

Ok, I have champions in her now.

[jrhd97]

pssst...hey buddy....you do realize that this is a dodge lovers forum...right?
Yeah, Yeah. The only thing I love more than my money pit is my old lady. It's a toss up on which one spends more of my money. :D

[Speed Dragon]

Yeah, Yeah. The only thing I love more than my money pit is my old lady. It's a toss up on which one spends more of my money. :DLol :thatfunny