TROUBLE STARTING

[NCTWITCH]

Hey guys, i was wondering, when i go to start my truck a few times during the day and in the mornings it takes about 2-3 times before it starts up and then i have to hold my foot on the gas for a little or it will stall, anybody know the problem, i have a 86 chevy c10 305

[Lt.Del]

Choke adjustment or vacuum leak
fast idle not working

[NCTWITCH]

so i have a quad jet 4bbl, i dont have to go thru emissions, so some thinks i have ran to the canister from the carb and others i just have blocked off, but i cant tell if there is a vaccum leak, and the choke you set with a screw right? the other day i was fooling around with it and set it real low and it was real quite and bogging down so then i turned it as far as it would go and it seems fine i think

[Lt.Del]

to check for a vacuum leak, turn on your engine and idle and take some wd40 and lightly spray around your vacuum lines and carb gasket, egr block off, if no egr, etc.  If you hear the rpm's go up, you found a leak. 

Choke adjustment is not with a single screw.  That is idle adjustment.   Choke adjustment depends...usually there is a black round part on the carb that controls the butterfly of the carb.   If cold, the butterfly should be closed.  As engine warms, the butterfly should open to allow more air in.  If it is open at all with a cold engine after you hit the throttle, it will be very hard to start.  It should be closed when engine is cold.  Also, if it is closed when the engine is warm, adjustment is necessary as well.

You can loosen the little screws on the round choke housing and turn one way or the other to close, open. then retighten.
 

[NCTWITCH]

DO YOU HAVE A PIC OF THE CARB AND HOW THE CHOKE WORKS, I DONT KNOW MUCH ABOUT CARBS AND THESE TRUCKS VERY WELL

[NCTWITCH]

I was also told that on the quad jet that the idle adjustment was the 2 socket looking things at the bottom of the carb on each side, the screw i was messing with is only 1 screw on the right side of the carb, will a little spring behind it

[Lt.Del]

the once screw with a spring is your idle,  the two screws, one on each side, is air/fuel mixture.

If you have a mechanical choke, there is a coil of metal inside the round thing.  Each side of the metal strip that makes up your coil is a different metal.  One metal on one side expands at a different rate than the metal on the other side of the metal strip/coil. The difference in expansion causes the metal coil to eithere tighten [coil tighter] or loosen, expanding.  That is why your butterflly opens and closes.  If your choke is electric, well, it is electric.