qjet tuning?

[ocbaud]

okay, i've read through mike's articles A LOT! but i just need to know the easiest and quickest way i can tune my carb. i need to tune everything on it, from the idle, to anything else i can.

the truck started diesling again couple days ago, and i messed with the timing a little at lunch and its running a lot better, but it still isnt "there"

the truck has been idling in park at about 1500rpm's which is way to high to me, when i drop it down to drive it goes to about 900rpm's

[Prerunner1982]

damn and i thought my 1000 at idle was high...

[J-Spec C10]

Mine is doing the exact same thing, I rebuilt it two months ago, and last week it started dieseling and idling high. Thanks for the reminder, I'm gonna go see if I can fix it right now.

Good luck, keep us posted.

[ocbaud]

Originally posted by J-Spec C10
I'm gonna go see if I can fix it right now.

mind telling me how i can do the same thing?

[low 84]

to fix the high idle all you have to do is back out the idle speed screw some. i can't exactly rember where its at on the q jet, but look at the throttle linkage on the side of the carb and you will see a screw that stops the trottle from receeding further at idle, back this out some and your idle will come down. if you idle is really that high it could be causing your dieseling as well. if its too high idle with the choke on, i believe there is a screw on the passenger side on the carb close to the bottum that you can back out some to reduce the choke idle speed.

[ocbaud]

Originally posted by low 84
to fix the high idle all you have to do is back out the idle speed screw some. i can't exactly rember where its at on the q jet, but look at the throttle linkage on the side of the carb and you will see a screw that stops the trottle from receeding further at idle, back this out some and your idle will come down. if you idle is really that high it could be causing your dieseling as well. if its too high idle with the choke on, i believe there is a screw on the passenger side on the carb close to the bottum that you can back out some to reduce the choke idle speed.

the normal idle screw(drivers side) was already backed out all the way.

i backed out the choke screw and the truck is idling at about 900-1000 rpm's in park and around 500 rpm's in drive. i took it out for a drive and its driving a lot better. and when i went to shut it off, it didnt even act like it was about to diesel

[82 Silverado 4X]

Eric
I followed the instructions (beleive it or not) word for word, step by step directly from my Chevy Truck Haynes Manual for the carb on my truck and couldn't be happier with it. Just be sure to cross reference the ID # to get your proper settings. Q-Jets are great when they are set right, but when they aren't they are a pain to get them back to where they belong.

[J-Spec C10]

I fixed the problem. Make sure your high idle kickdown is adjusted. Mine was a little high, also I found a few slightly loose top-plate screws too. Its all good now, runs smoother too.