i think the both control gas. before you start you want make sure the engine is warm and that the choke is open. you will want to adjust both 1 at a time. what you are trying to do is get the engine to idle as high as possible. when you adjust the one side to idle as high as you can then you go and do the same to the other side. then you just have to adjust the screw on the throttle to bring the idle back down so the truck is drive able.

 

I think an explanation of basic carb operating principle might help. Mixture screws are needle valves that allow very fine control over the openings thru which the fuel passes. By varying the opening you control the amount of fuel that can get thru the little hole at one time and these openings are like nozzles.

When you step on the gas peddle the throttle plates open and this allows less resistance to the flow of air. Because of the venturi shape of the carburetor throat Bernoulli's principle comes into play. (i.e., as the velocity increases, pressure falls) The venturi raises the air velocity, and this high speed and thus low pressure sucks fuel into the airstream through these nozzles located in the center of the venturi. This explanation is for a single barrel carb and yours has two sets of each.

When you really step on it an accelerator pump adds additional fuel to prevent stumble because the nozzles will not flow enough fuel quick enough for acceleration. Hope that helps.

 

so a carb can be at such a high idle, that it isnt drive able? guess thats what happened earlier when i pressed the peddle and it died. guess ill try again tomorrow. also, i plan to call around to the boneyards to check for 4bbl intakes.

and that is a VERY detailed anatomy of the carb and how it works. im copy and pasting all this info in my documents for reference. appreciate all the info.

i havent tried the timing...thought about it off and on but havent given it a whirl. may have to though. may be the problem all along.

 

it would be drive able but if it is idling too high it will be like your throttle is sticking which is not good for everything from your brakes to the motor mounts.

 

When the mixture changes it effects the idle. When the idle changes it effects the timing. This is why the timing must be set at a certain idle. These things are not separable. They must all be right to make the engine idle properly and run well.

 

that makes a freakin massive amount of sense. i would assume your body would not operate as normal if your heart was beating e-regular and your lungs were not inhaling the proper amount. you would most definitely be my dodge truck..or dead lol today is my only day off and im going to get one of these problems SOLVED!!!

 

well, i ran the truck to operating temp. offed it and idled it ALL THE WAY DOWN. crank it to make sure it was deadly low. then offed it and gave it about 2 even turns idling up on each side. cranked it up and it was sweet music..no soot coming out the tailpipe and it had a pretty even idle although it is still backfiring out the carb a bit.

 

it is good to hear that is is starting to run better. 2 turns might have been a bit too much for the carb. it might be running a bit too lean which might be causing the back fire or the timing could be a bit off.

 

gotcha. it was doing it no matter how much of which way i turn it. but i may turn them back about a half a turn or a tiny bit more. i really appreciate everything you guys have taught me. i swear, if it were not for yall, i would have shot that truck...literally...

 

once you got these trucks tuned in and running good they will almost run forever. i have put nearly 10,000km on my 81 since i plated it last June. no major problems. now that i got everything working good i am hoping to start doing some mods to save me some money in the long run.