Doc, what do these symptoms mean?

[Lost81c10]

1 - When I shut my truck off it wants to continue to run. It will sputter fo a times and it wil finnally shut off (reving kind of high).
2 – In the mornings I pump the gas once, truck starts and revs good for about five seconds and then it dies (I can keep it running if I kind of pump the gas once it starts to die). Once it dies, I have to pump gas one more time and then start it and it will stay running, not real smooth but eventually it someths out and revs go up.
3 – I feel like it is taking way too long to warm up and for the RPMs to come down. RPMs don’t come down on their own, I have to ckick it to make them come down, even after I drive it on my ten mile comute to work the revs are still high so if I don’t want the truck to sputter after I shut it off I leave it in Drive and shut it off.
4 – Lastly, white smoke smelling like fuel fumes comes out when I first start it when thruck is cold.

Patient is 85, 1/2T, 305, Q-Jet.

thanks for the help.

[86c20]

try turning the idea down some and that should stop the run on

[JRANGER]

Sounds like a timing issue or a carb tuning issue....Mine is doing similar since I replaced my carb

Could possibly be the cold weather but im just making educated guesses from what Ive heard/read....

[BMERDOC]

86c20 was trying to say idle not idea. The "run on" term is called "dieseling". (not trying to correct you 86c20, just clarifying for our friend here) Your idle is too high. Your choke is probably out of adjustment. If the carb has been on your truck for a while and just started these symptoms it may be time for rebuilding or replacement.

[86c20]

bmerdoc its all good. if some one gets me its a good day lol. but yea that is what i was trying to say.

[Lost81c10]

so the idle being to high is taking an effect on all of my symptoms or are we targetting one specific. also you mean the idle on the choke side correct or the idle screw once its hot, see i dont know the proper terms either so hope you know what i mean.
as far as the carb, i had it "rebuilt last march, by a mechanich that said "Q Jets are my experties" but it has not been performing at its peek even fater the so called rebuild. we went back and forth on settting it right but not he just couldn't getting, "excuses/try it and see how it does" we i got tired and stop going back.
thanks.

[motornut]

Originally Posted by Lost81c10

1 - When I shut my truck off it wants to continue to run. It will sputter fo a times and it wil finnally shut off (reving kind of high).
2 – In the mornings I pump the gas once, truck starts and revs good for about five seconds and then it dies (I can keep it running if I kind of pump the gas once it starts to die). Once it dies, I have to pump gas one more time and then start it and it will stay running, not real smooth but eventually it someths out and revs go up.
3 – I feel like it is taking way too long to warm up and for the RPMs to come down. RPMs don’t come down on their own, I have to ckick it to make them come down, even after I drive it on my ten mile comute to work the revs are still high so if I don’t want the truck to sputter after I shut it off I leave it in Drive and shut it off.
4 – Lastly, white smoke smelling like fuel fumes comes out when I first start it when thruck is cold.

Patient is 85, 1/2T, 305, Q-Jet.

thanks for the help.

2.pump once? I pump 2-3 times,while starting,low idle till running on electric choke? cause it takes a bit to engage

3.revs or choke won't turn off till you hit the gas and knock it off,stuck on will smell gassy,and diesel

[BMERDOC]

Being that it was "rebuilt" you may have to start over and check all the settings on the carb. Because it is a Quadrajet you'll wanna check the throttle shafts first by wiggling the shaft to check for excessive play. If you are getting air seepage through the throttle plate past the throttle shaft you adjustments won't matter.

[86c20]

Originally Posted by BMERDOC

If you are getting air seepage through the throttle plate past the throttle shaft you adjustments won't matter.

been there with a holly

[BMERDOC]

http://67-72chevytrucks.com/vboard/s...d.php?t=553926

This quadrajet thread is currently active and has some good info.

[willett]

Sounds like my truck

Check to see if your throttle linkage is sticking I know mine does when it's cold. I actually use the 'high idle' to my advantage to warm the truck up and prevent it from stalling when cold. I know I'm up to operating temp when the throttle stops sticking.

Also shut your truck down in gear and it won't diesel anymore. If you let it diesel you could potentially bend a valve
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[willett]

Obviously a band-aid fix but you do what you do when you can
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[bigguns]

In my experince with rochester carbs.If your engine continues to run after you shut the key off your float is no good.Its sinking and allowing the fuel bowl to over fill.When your air cleaner is off the carb and you shut the engine off is there vapor coming out of the carb ?If so then it's your float.

[tucsonjwt]

Easy first step - remove air cleaner and check to see if the choke valve is fully open when the engine is running. IF not fully open, pull the throttle back all the way with right hand and move choke valve to the full vertical position. If the choke valve will not stay open, the your choke needs adjustment. I gave up on automatic chokes long ago and spent $12 to convert to a manual choke - my recommendation.

[Lost81c10]

Originally Posted by willett

Sounds like my truck

Check to see if your throttle linkage is sticking I know mine does when it's cold. I actually use the 'high idle' to my advantage to warm the truck up and prevent it from stalling when cold. I know I'm up to operating temp when the throttle stops sticking.

Also shut your truck down in gear and it won't diesel anymore. If you let it diesel you could potentially bend a valve
Posted via Mobile Device

thanks for the info, funny you mention that because some time ago i had an issue where the truck was revving way up and i could not tell why so i turned the idle down and fixed it but after that i noticed the next day that it was way down so i was puzzled so turned the idle back up not long after that i was like Duah, i had the ac engaged and the following day i had it off.
So I think I will try that during warm up and shut it once warm.
as for the dieseling, i did not know that it could bend the valves, luckily i had been doing just that but once or twice i would get mad and just let it die on its own...no more though.
i have been playing with the choke and its idle screw a bit at a time and its getting better.
Thanks to all for the info. i'm still playing with it and still will have to get my carb relooked at by a competent mechanic once i find one around here.