Keeps shutting off

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RustyNail84

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Ryan
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1984
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K10
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350
I have a 84 Chevy k10 350 5.7. I just but a new motor in about six months ago and it's been running great until this morning. I just put gas in my truck and drove for about 40 minutes and stopped at Walmart. When I came out and started it back up it was running fine then once I got up to speed it and let off the gas it sounded rough and shut off. It won't start back up until I held the gas peddle all the way down and turned it over till it fired. A little black smoke came out the pipes I'm guessing bc there was so much fuel in the carb but as soon as I let off the gas it shuts off again!

Does any one have any ideas what it could be?
 

74 Shortbed

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Float stuck, try tapping the carb..
 

theblindchicken

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Had a float in mine that would get stuck going over speed bumps. Turned out it had swelled. Replaced it with a new one and worked perfect.
 

HotRodPC

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The way you describe the problem and to get it to restart, it does sound like a flooding problem and that is indeed usually caused by stuck floats and dumping to much fuel into the intake and gas fouling the plugs. By holding the gas pedal to the floor you're clearing out the flooding and it's starting again. That's only going to happen so many times, then the plugs will be saturated to the point it can't start back up.

One other thing, you mention the black smoke which is also a very rich condition. Is it possible your choke butterflies are closing? Full Throttle can also open those too. So check the stuck float issue and take a look at your choke linkage too. For purpose of diagnosing or a quick patch job, you can wire the choke butterflies open and see if the problem goes away.
 

Honky Kong jr

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Don't let it get to o the point where it washes out the cylinders if it does you won't have happy rings and cylinder walls. And after you get the t fixed change the oil it's probably gas saturated.
 

HotRodPC

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Don't let it get to o the point where it washes out the cylinders if it does you won't have happy rings and cylinder walls. And after you get the t fixed change the oil it's probably gas saturated.
Yep, if flooding is indeed the problem, the gas will leak down past the rings and thin the hell outta your oil and gasoline doesn't lubricate well. This would be an extreme case, but don't think it hasn't happened before.
 

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