Need help with 85 350

I have a 1985 chevy c 10 with a 350 engine in it. the truck idles fine but when i tromp it done it stalls out. I noticed after taking the air cleaner off the the butterfly valve in the front of the carb is stuck
wide open. the linkage goes straight down and back to a little vacume. if I close the valve almost all the way the truck revs up just fine and barks pretty good. What is the problem with the carb?
Thanks for any help.
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Lenny wrote:

First off is the butterfly valve(refered to as choke valve) wide open when it was cold or after warm-up? If the engine is warmed up the choke valve should be completely open under 96% of conditions. If the engine was cold then there are several possible causes. First check to see if the cams on the left side of the carb move freely. the largest cam usually has a letter stamped on it and is the main cam for the choke lever. Second check to make sure that the green link going to the dash pot or vaccuum operated diaphram in the back is free to move ...but dont bend unless absolutely necessary.Next ( when cold ) open the throttle lever all the way and then let it snap back do it twice to make sure. This will set the choke cams so that the choke valve is open. Now return to the main cam lever with the letter on it press down on it slowly you should feel three distinct steps or choke positions as it goes down. At each step the choke should close a little more. If the lever does not stay down then it is time to check the choke coil spring on the side. It will be the black disk shape that is in a housing that sticks out on the left side, it will be held in place by either rivets or screws. If it's held in place by rivets just knock the off with a chisel or a drill with a larger diameter than the rivets.*****be sure to save the little gold clips beneath the rivets or the screws. Once you remove the coil cover you will find a coil spring underneath make sure it is not broken and has at least some resistance when wound 1/4 of a turn. If it seems bad it is better to replace with new. If you wish not to replace it you may re-attach with the clips and some small self tapping screws...make sure the little tang or cup of the coil spring catch the engagemant lever in the bottom of the choke housing. Now tighten the choke spring (by turning to the right) about 3/4 of an inch to the right and tighten the screws. Once again reset the choke by snapping the throttle lever wide open and shut now try the cam lever once again to see if it is tight enought to close the choke all the way on the last step ( lever all the way down). If not you may have to wind the spring a little tighter. Hope this helps if not there are several other things that could be wrong such as a low float level or clogged jets or mettering rods if this doesnt work post again and I'll try to walk to walk you through these other steps but at that point you may want to have it looked at by someone with some experience as it gets even moree complicated .....good luck!
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snipped-for-privacy@gmail.com wrote:

Thanks for your help but we decided not to buy this truck from our boss anymore. And yes it did run but only idled.
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Did you get this running right
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