Technical Fouled plugs, nasty

So my flathead was running rough last fall. I did a long overdue tuneup, and found only one screw holding the cap on, so it was floppin all around while the car ran. Tuned up, fixed that, and it ran great all fall, as it normally does. Kept it in the garage this year and went to fire it up on a warm day. Didn't want to start great, but did. I let it warm up, then idle a bit, killed it. Went to start it last weekend and it started, but an obvious miss. Pulled the champions out today expecting a fouled plug or two, and all eight were soot black. Richer than Steve Jobs. I replaced the plugs and right before I started it up I noticed the ground hangin off the choke..... Damnit.

Will that do that to the plugs that bad and quickly? I've never had any problems with it before, and after fixing it and putting plugs in it drove around the lake perfectly, so I'm feeling like that was it. No blue smoke out the exhaust or any other telltale signs of rich issues....

 

Yes, they'll get carbon fouled pretty quickly if the choke doesn't open. But they'd probably burn clean pretty quickly too, if you put them back in and it starts.

 

WHY...do people start an engine, let it run for three minutes, then shut it off ?
What do you OR the engine get out of it ?
One of the big things that the engine gets..."fouled" spark plugs, that's what.

Nothing else happens, except that the plugs get fouled (if the choke is working), the acid that is formed on cold start, that is not warmed to full running temperature for 10 or 15 minutes can damage the bearings, the cam and lifters, the exhaust system, and on and on.

Make sure that the choke is properly adjusted.
Clean the plugs with a clean stainless wire brush, put them back in the engine, start the engine, and put about 20 miles on the car. Then check the plugs, they should be almost clean.

And DON'T, start the engine for 3 or 4 minutes once a week, then shot it off until summer..!!
DON'T start it at all, unless you can actually put a few miles on it before shutting the engine off.

Mike

 

Spray the plugs out with brake cleaner, and shove them back in.

 

I would remove that electric choke and put a cable on it.. Those electric chokes never worked for me...

Instead of pulling the plugs, get it good and warmed up and take it out on the highway and give it a good workout. This will clean the plugs and everything else..

 

Thanks for the responses. I chucked the plugs. Twenty bucks for a set of the ngk's, no biggie. I'm fine with where it's at after reading responses. I'd imagine that's it for the issue. I knew that'd foul um, but I didn't think it'd be that bad that quickly.

I must say, I do not like the 4bbl. It was on there when I got it and I'm hesitant to mess with a car that's run fine since I've had it, but a pair of strombergs is certainly on my mind constantly.

Mike I started the sucker because it was nice out and it had sat without running for months, and I actually intended on taking it out, but right when I was gonna go someone popped in, Yada Yada Yada, I turned it off and got caught up shooting the breeze n drinkin beer. I don't run it a few minutes a week, etc, lol. So you may rest easy!

 

I have found that cars are like kids...no one knows them better than you do....

 

If you don't mind chucking $20 , you can chuck it my way ,I'll take all the chucked bucks I can get ! That's 4 days groceries !

 

I'll give ya twenty bucks, sure. Drive on up n git it...

 

toss the Champions for Autolites.

 

The spark plugs don't know what brand they are...and the engine doesn't know what brand they are...so it's not likely the problem.

 

I don’t live in that kind of environment, but don’t you think after all the years of salting roads and issues it causes , coupled with all the technology we have now, there would be an alternative solution to salting?
Hell, maybe road salting is funded by by GM, etc. mercy.

 

So an update. I ran the ngk 6's and everything has been honky dory. I don't know how many miles I've put on it since, but not enough that they, yup, foukd again. Went to start it yesterday after sitting a few weeks, and ran like chit. Haven't pulled um yet, will tonight, but absolutely expect them to be black.

I'm head scratching now. I'm going to double check my timing, and I'm sure it's not the carb jetting or fuel pump, as it's been fine up till now, and runs fine with the fresh plugs.

I'll update after fresh plugs and timing check, but I have no idea what's fouling these things....

 

Double check the choke for proper operation also. Possibly it's not opening as it should when the engine is warm and needs adjustment or linkage is hanging up keeping it partially closed.

 

Make sure you've a good, HOT spark ignition. Good grounds and correct heat range plugs. A defective ignition coil is at least a possibility. They can be tough to diagnose. An ignition scope is great way to quickly eliminate subtle (or not so subtle) ignition defects, because it can be tricky to find them sometimes, and a defective ignition or weak spark will make it appear just like the carb is running too rich. If you know the ignition is squared away, by testing, then you can also logically start focusing on carburetion.

Jetting doesn't factor at all at idle, but incorrect float level or excessive fuel pump pressure, defective power circuits, incorrect idle mixture etc will foul plugs very quickly.

 

Does it even need a choke? With a 4bbl on a flathead, a coupla pumps on the accelerator ought to do it. You could wire it open and give it a try...

 

A defective condenser will foul the plugs also. Heavy soot, weak spark and a poor running motor. I don't know squat about flatheads but I just assume there is a condenser for the points system.

 

No points. All msd.

 

I dunno. What perplexes me is it's been fine till now. I think the gent above may have a point with choke position so I'll check that first.

I've had one of those weeks. Everything has busted. My Chris Craft needs rudder and shaft packing so was filling with water. Damn boat lift cable broke, the the shoebox. One of them weeks.... Ugh.

 

So the plugs were black, not as bad as last time, and some worse than others, tho none right. Set the choke up, it's fine and functioning properly, though at first it acted like the plate was stuck open. Car started and ran great, no smoke whatsoever from the pipes. I noticed some gas coming out of the secondary bowl and checked the bolts holding it on, and they were pretty loose. Primary bowl too. Tightened those up. Still was weeping gas from this sucker....

Edit: set the floats, the primary was definitely dumping heavy. Car is idling smoother and throttle response seems improved, not driving of course. Secondary seemed OK, if anything a touch light, but I let it be.

Edit: gonna have to replace the secondary bowl to stop that gas weeping from the input plug. Damnit. If anyone has a secondary bowl for a 390 they want rid of pm me! Is it the same as a 4160, etc? Are they all the same bolt pattern?