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DC Pit Crew
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Discussion Starter #1
Went and drove around for a bit with a friend's white convertible '69. When we parked and turned it off it would sputter and rumble for 5 or so seconds. What causes that? Is the mixture too rich and it's just burning off residual gasses? What's up?
 

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My two cents is it could be running too rich. I just had this problem with my Edelbrock carb and just changed it for a Holley. I leaned out the Holley and the stumbling after shut off stopped. Runs a lot better also.
 

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Often overlooked: When you shut the motor off the crank pulley still spins a little, turning the alternator which sends a little current to the distributor. Kind of a vicious cycle. This can keep the car "running" for a few seconds. Happened to my 69 Camaro. The fix was a one way resistor up at the alternator. That might be a good place to look also
 

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I had a Chevy 350 that did this as well. My grandfather, who worked at the Arlington Texas assembly plant for GM for 35 years said that the mechanics called it dieseling amongst themselves. It was easily fixed by adjusting the carb to lean out the fuel delivery.
 

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DC Crew
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SCharger said:
I had a Chevy 350 that did this as well. My grandfather, who worked at the Arlington Texas assembly plant for GM for 35 years said that the mechanics called it dieseling amongst themselves. It was easily fixed by adjusting the carb to lean out the fuel delivery.
:agree:
Also slow your idle speed down, sometimes 50 to 100 RPM will do it!:thumbsup:
 

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its commonly called dieseling. Sometimes it can be caused by a rich running carb still sending fuel into the motor, and if its hot or the ignition system hasn't shut off due to peculiarities in its design, the engine will continue to turn, however slowly, until the carb is starved of fuel, or the engine is started and shut down again (had to do that one before).
 

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I believe it can also be from the build up of carbon deposits in the combustion chamber.This remains glowing hot after shut down, acting as a glow plug in a diesel hense the term "dieseling"
 

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its definately the timing i screw with my idle, and mixtures and **** all the time its the timing no doubt about it
 

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DC Pit Crew
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Discussion Starter #10
Thans for the info guys. I'm not sure when I'll get the chance to look at this car again, but I'll keep this thread handy so I can reference it when I do
 

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Amazing how quickly those of us Newb's experience the same problem... I'm running into the exact same thing. I had read the post about a week ago and this morning what do you know. I'll adjust the carb this weekend and let you know if I can get it fixed.
 

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There is no timing after you have shut the ignition off, no iginiiton , no timing. Your newer to automotive have forgot the anti dieseling soleniod that used to be on carbs, it closed the throttle plates at shut down to shut off the fuel mixture. If have do not have this soleniod, reduce idle speed and the problem is solved, if you have to much cam to reduce the idle speed, find an old parts guy, and find an anti-dieseling soleniod and attach it to you carb. Remember, use the soleniod to set base idle speed, then set your carb idle speed screw so the engine will die when the soleniod is de-energized. Problem solved.

Remember, it can not be timing, the key is off and the ignition is dead, No Timing.
 

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Discussion Starter #13
jimfeiii said:
Amazing how quickly those of us Newb's experience the same problem... I'm running into the exact same thing. I had read the post about a week ago and this morning what do you know. I'll adjust the carb this weekend and let you know if I can get it fixed.
let the fun begin! I hope you don't mind spending a little quality time under the hood, Jim. As I'm sure you're aware, these old guys are a real hands-on deal. It's a great feeling when they're running right, but they're definitely a little more time consuming than the modern ones.
 

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Discussion Starter #15
rjent said:
Who are you calling OLD buckwheat! :D JK
the cars! the cars are old!:laughing: The owners are just "worldly".:lookinup:
 

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lsejlowe said:
the cars! the cars are old!:laughing: The owners are just "worldly".:lookinup:
From one young Jason to another..............That was awesome!!!!!:rolling:
 
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