Ignition problems again. Please help!
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Joined: Jan 2001
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From: Virginia
The above is trying to tell you something. I am not sure exactly what; a vacuum leak? The idle mixture screws need a little tweaking?
Cargo Master
Joined: Dec 2004
Posts: 3,362
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From: Florence, SC
Originally Posted by oneofakind97
It's starts up and idles fine and then the idle gradually drops and I assume that is the spark dying off? Then it misses throughout the entire rpm range and runs really really rich. Blows a lot of black smoke out of the tailpipe.
Originally Posted by oneofakind97
IAll the plugs had carbon all over them. That was about it. I figure that's just from the way it idles. I haven't even gotten to drive it much. It's always just idling in my driveway.
Edit: the carb is a holley truck avenger 670. I put it on the truck right out of the box and didn't mess with the jets any. The only thing I did was put a different accelerator pump cam in it.
Edit: the carb is a holley truck avenger 670. I put it on the truck right out of the box and didn't mess with the jets any. The only thing I did was put a different accelerator pump cam in it.
A 5.0/302 doesn't need anything bigger than a 600 cfm carburetor; and even that is pushing it.
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Senior User
Joined: May 2005
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When it's firing on all cylinders it doesn't run rich at all. I only have these symptoms while I have intermittent spark. I would assume it's caused by the fuel being only partially burned during combustion.
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Joined: Jan 2015
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My uneducated guess is (can't see or hear over the net) is it runs rich until a plug or two gets fouled and then begins to miss. Above post that a new dizzy would result in another bad dizzy is based on a piece of advice given to me about fifty years ago, "boy most distributor problems are located in the carburetor and most carburetor problems are in the distributor."
Try running it with 450 cfm, just for grins.
Try running it with 450 cfm, just for grins.
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