nick366

Hey guys, ive got a problem with my carb. Its a holley 650 and i cannot get the thing to idle right. Im still learning on carbs so hopefully its something simple. When i first turn the car on to warm it up it will idle right at 900 or so, but then when i start to drive it will not idle lower than 1250-1500 when im at a stop. The carb is suppose to rev a bit when it is first turned on to warm it up faster and then kick down. I've tried playing with the idle screw and cam idle screw but cannot get it to run right. Any help would be much appreciated. Thanks

fourfivefour

Check the linkage for binding. Install a return spring on the throttle arm. Are your floats adjusted properly? Do you know how to adjust the mixture screws?

ddeaton66

Do you have an electric or manual choke? If it's electric then the engien compartment has to warm up before it returns to a normal idle. Also all adjustemnts made to the card should be made @ normal operating temps. If you adjusted the ide while it was cold initially it might be the culprit.

nick366

its an electric choke and i have already put on a return spring. Even when it warms up it still doesn't idle norml. I do not know how to adjust the floats or mixture screws.

fourfivefour

How to check/adjust your Holley float level.

2 kwik

first close the air screw all the way in lightly then open them 2 turns to start do this while it's running if you tighten one with no idle change there lies 1 problem

hellas85stang

get a vacum gauge check it to see if its surging up n down,,if so theres a vac leak..and if its a edelbrock adj each side till dies a lil and back it off a cpl turns..if it doent then yes carb needs a rebuild...carbs are easy to adj..ya nneed a tach,and a vac gauge,,and a lil knowlede... go to fletchs 5.0 carburated mustang site..theres a wealth of info

PONY GUY

+1 i was going to say the same thing

2 kwik

650 as in a spreadbore?

fourfivefour

How to adjust your idle mixture.