How easy is it to gas foul a spark plug?

[greenpigs]

   I was getting my Holley tuned in and it was running SUPER rich, gas out the vent tube. The float level is kosher now and I went to one step bigger jets than was stock in my 3310-3 to be safe. Now I guess my plugs may be gas fouled...the car didn't run long due to a gas leak. So could a few minutes of running ULTRA rich foul the plugs? From what I found they are most likely fouled and the general opnion is to replace them, as cleaning is hit or miss. I am running NGK 5's now as they were recomended by Mancinis for the low CR motors. I am getting blue smoke when reving the car and it has 73 & 76 jets...on the small size. It doesn't smoke at idle so I am thinking this is due to the plugs being toast. I have good spark and the battery is up to snuff so about the only thing is the plugs its just I don't know how easy it is to foul the plugs.

[billschroeder5842]

My '69 will eat up plugs if my mixture is off. I can usually solve the problem by removing and cleaning---I don't need new plugs.

[Ghoste]

The ease of fouling plugs is directly proportional to how desparately you need the car to start.

[elacruze]

You had the perfect situation for fouling plugs.

Rich mixture, short run time, some oil in combustion.

If the porcelain of the plugs does not get hot enough, when you shut the engine off and they cool the wet gas/oil that didn't get burned off crystallizes when they cool. They won't necessarily quit while running, but will fail to re-start after cooling.

Does that sound like what happened? If you can clean them and get it restarted, they should be ok after they spend some time at operating temperature, unless the heat range is too cold anyway. 

Before you remove them to clean, try this old trick- Hold your coil wire out of the coil about 1/4 to 1/2 inch and let the spark arc across the gap. If it starts, stick the wire back in and drive on. The additional gap forces a much higher voltage and will usually then jump the spark plug gap even when fouled.

[greenpigs]

Thanks

  If I gotta go through the hassel of pulling them to clean up I figure might as well swap in new. They don't take much to foul out from what I am finding.

[Plum Crazy 68]

I recently started my car after 8 years of sitting.  Ran out the bad gas etc. and retuned the Holley 4150 that I had put on it years ago.  I was getting a little bit of cough that I originally thought was the bad fuel.  After a few different tweaks and replacing all the vacuum plugs and lines, I started getting really rugged running.  I had a little oily exhaust so I figured I fouled the plugs.  I replaced them and at the same time I moved the vacuum advance from the metering port down to the lower vacuum port at the front of the 4150.  Runs top notch now!  So I think it was a vacuum issue all along and not so much the plugs.  I even had to talk nice to her a little.  I'm going to use a vacuum gauge now to see if I can get the idle mixture just where she wants it.  She says she likes it there better too.

[CB]

The ease of fouling plugs is directly proportional to how desparately you need the car to start.

Lesson learned! The hard way

You had the perfect situation for fouling plugs.

Rich mixture, short run time, some oil in combustion.

If the porcelain of the plugs does not get hot enough, when you shut the engine off and they cool the wet gas/oil that didn't get burned off crystallizes when they cool. They won't necessarily quit while running, but will fail to re-start after cooling.

Does that sound like what happened?

That's what happened to me right now. Messing with the charging system and had it run shortly for a couple of times. She won't re-start now. Pulled the plug and yes, wet from fuel/oil. 

See if I can find plugs tomorrow.