Why does it do this

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btorres31

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Brandon
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86 chevy long bed 2wd
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Good morning guys

I will attach the videos of truck acting up, it only acts like this when it is first started, once warm it’s fine, just had the stock carb rebuilt. Any suggestions guys?

It won’t let me post the video, but the truck shakes and blows blacks smoke only first starting, once warmed it drives like it’s brand new. Any help would be appreciated
 

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squaredeal91

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Sounds like choke adjustment. Your spark plugs are probably turning black. I bet if you look down the venturi of your carb you'll find it to is starting to darken with black carbon.
 

fast 99

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Does sound choke related. Choke thermostat could be too tight, choke pull-off needing adjustment or fast idle too low. Choke plate should close when cold but not too tightly, after starting pull-off should open plate sightly. Choke thermostat may be indexed and not adjustable. When cold, either with a vacuum pump or by hand actuate the choke pulloff. It should open the choke plate slightly. A 3/16th drill bit is a decent gauge for choke opening. Use it between the choke plate and upper housing in rear. If not opening enough there is a Phillips screw on the pull off. That's where it is adjusted. This will be a base starting point. The loading up should improve. May also need to adjust fast idle.

One thing to keep in mind when an engine loads up gas will get past rings and dilute the oil. If it's done this several times an oil change should be performed. After that, readjust the idle mix.
 
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JBswth

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Good morning guys

I will attach the videos of truck acting up, it only acts like this when it is first started, once warm it’s fine, just had the stock carb rebuilt. Any suggestions guys?

It won’t let me post the video, but the truck shakes and blows blacks smoke only first starting, once warmed it drives like it’s brand new. Any help would be appreciated
Make sure the choke's vacuum break works. Put some rubber tubing on it and suck on it. You should see the little clevis retract. If it doesn't, the diaphragm is gone. It needs replacing, as it can't be opened up for repair.

J.B.
 

greyghost

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vic
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electric choke uses 12v power supply key on activation, adjust by loosing 3 screws turn CCW and CW watch choke plate move from open to close, at point it is completely closed back off slightly tighten screws, adjust when temps are *32...it will take few times adj. for year round functionality
 

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