I keep fouling one plug. It's #1 cylinder. The engine is a Pinto 4 cylinder. It has 2 40mm Solex side draft carbs, which is basicly 1 single barrel carb per cylinder. Compression is the same in all 4 cylinders. Carbs are set up the same. Ignition is in great shape. Seems to do it at low RPM's. High RPM's it runs great. It isn't the plug itself, as I have swapped them around in the cylinders. I'm thinking it's the carb. Not sure what to look for. I thought about turning the idle screw in farther on this cylinder. The fuel flows into the carbs to #1 first, but that shouldn't matter. One thing I just thought of, and am going to look at right now. The chock cable is metal, and it might touch #1 plug wire. I wonder if it's grounding out? I'm going to go and put some rubber hose on it, and clean the plugs again and try that. Thanks, Dean
Switch plug brands. Selling parts for the last 18 years I have seen a decline in quality in the autolite line
Thanks. I've already done that, and had the same problem. I think I was using NGK, and Champion. I bought these from Summit racing, they're Ford racing plugs, not that it makes them any better, I just couldn't get them locally, and other guys had ran them with good luck.
To be perfectly honest, they are all too foul to read. They appear dry so i'd start leaning the idle circuit. I'm no expert on those carbs but i believe they are a little large for your combo, just downjetting may not get you where you should be. If the engine is running cool i'd try hotter plugs, but i'd be leaning the idle circuit and go from there.
Autolites are good plugs. Its all I use in my Ford engines. If its a Chevy I use Champion or Accel. I would be happy with those plugs, but, that one cylinder perhaps needs a new spark plug wire, or the rotor isnt connecting well in the cap. Keep in mind, If the engine idled befoire pulling the plugs, it isnt a good read. It will show rich, and if it doesnt, I bet your cylinder is runnin hot down the road. If the first carb is the one in the cylinder where the plug is black, and if they are fed in series, then perhaps your needle cant hold the pressure? try a fuel block feeding them all the same. The only way to truely read a plug is, run the engien through the gears, and at WOT, kill the engine, pull over and pull the #1 and read. Any idleing ruins the read.
I had EVM injectors on my 2 liter Pinto. The first one interfered with the distributor. Maybe you are shorting out to the first spark plug wire? I cut the distributor bowl off of the lower part. And made a new one that was 1/2 inch shorter. held it to the bowl with 4 8-32 screws. Had to cut 1/2 inch from the oil pump drive shaft.
Well the choke cable was touching the #3 plug wire, so that wasn't causing the problem. I did put rubber hose on it though. I'll look at the cap, and the plug wires tomorrow.
I don't know anything about those carbs, but I would swap their position. Put the one in front now in back. If you see the same thing it isn't the air/fuel....checked your wires? Ignition?
If #1 is fouling its not shorting as it is firing and buning rich.My suggestion is the same as hotrodbrad,swap the carb round,if its now #3 you now know where to look. May have a wrong jet or something. Good luck. JW
Shouldn't the ground electrodes extend further? They look kinda short and the gap looks too big. Definitely something not right with the one cylinder compared to the other three though.
I'm thinking about doing this. It's not hard to do, but lots to change, linkage, some brackets, and a few other things from carb to carb. But that's my next step. It's the only way to know if it's the carb doing it. Maybe I'll do it tomorrow. Thanks guys.
well i just put autolites in one of my cars and taking a break i was reading the box and it said contents made in china!!!! oh yeah and id swap the carbs around also to see if the problem moves around.
have you completed step 4, here, for each idle mix/pilot screw ? http://www.mikunipower.com/PHHCarbs/PHHservice10.jpg
To me , it looks like the one plug might be carbon fouled because it looks sort of powdery, rather than oily. If it is just one of the four, I would check the distributor cap for cracks or a bad electrode causing weak spark. You could check that plug wire too. If all of that looks good, it could also be a possibility that you have a sticky valve... Robber
Go ahead and laugh, but if you must use this setup for RPM's less than about 2500, try making a metal shield to protect the temperature of the front carburetor from the airstream of the fan. Jon.
I didn't work on it today. Had other stuff I needed to do. I think I'll replace the distributor cap, rotor, and wires before I swap the carbs. Those pieces are cheap enough. The caps been on it a long time, but looks good inside, and the wires have been on it for awhile too. Then I'll switch the carbs if the problem's still there. Jon, not sure how much airstream from the fan goes over the carb. The fan is small, and so is the radiator, but at this point I'm open to anything. Funny I was just offered a job in Eldon. I passed on it. To far from here for a daily drive.
Possibly too rich of a mixture (too much gas). . . or maybe you're not running the car long enough to get the plugs hot enough to burn all of the carbon/ fuel deposits off. I'd put new plugs in and take it for a blast down the highway, then check it again.
It doesn't take much, especially at low RPM on that setup. Take a look at the shield Cadillac fabricated to protect the choke on their front carb on the factory dual quad setup: http://www.thecarburetorshop.com/Cad_1955_2x4_passengers_side.jpg Jon.
I didn't mess with it this weekend. A trip to Walmart this morning pretty much set the tone for the day. I hate that place. Maybe this week after work, or next weekend I'll mess with it more. Jon, I might make something up for a shield and see if that helps. Rejetting the carbs isn't hard either, so I might do that too. Swapping the carbs is probably going to happen soon. Thanks, Dean
I think carbking is on it. Those carbs are sensitive to intake air flow. If you run it wide open throttle and it doesn't foul then it could just be a needle/float issue. Especially with this junky gas they are selling us! peace