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8 fouled plugs

764 Views 5 Replies 6 Participants Last post by  TommyK
So this is my first post to this site. I have a 72 Fastback that I put a 429 Cobra Jet, bored and stroked to a 472ci. The engine was run on a dyno a couple of years ago. The problem I am having is I am fouling plugs almost immediately when I run it. I marked the distributor from where it was from the dyno shop so I believe it is in the same spot. I am thinking that I have an ignition problem because the carb has not been changed or adjusted since he dyno. I thought I might have hurt the ignition module because I shorted out the starter solenoid when I was debugging the wiring. It has a Pertronix distributor and I tried a new ignition module, but same results. It just acts like It is not getting voltage to the plugs. They are pitch black and dry. Any thoughts ?
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Welcome to the site!!
If the plugs are black, either the carb is running too rich, or the plugs are too cold. If you had an ignition problem the engine would be missing or not run at all, either one will not cause all the plugs to be black or fouled. If you have a timing light it would be a good idea to check the initial ignition timing to see where you are at. You also need to look at the exhaust when the engine is running, if it is black the mixture is too rich, either from a choke too tight or closed too much, or a carb malfunction, if it is a Holley it probably needs rebuilt, because the cork gaskets have cracked or shrunk. My 2 cts.
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Agree with above. DRY fouled plugs are generally an indication the fuel mixture is too rich. Check Air Filter, Choke, Carb adjustment.

I agree with the rich fuel air mixture. From what I read, it sounds as if the engine hasn't been run in a couple of years. If so, you may have a sticking float in the carb or a needle and seat that is not sealing and allowing fuel to overfill the float bowl and run into the engine unmetered. You can actually see this happening when you look down the carb throat with the engine running.
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What kind of carb do you have?
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