Hesitation and rough idle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

shortbed70 · 05-25-2003, 09:20 PM

The truck runs good down the highway but has a rough idle. I just changed plugs but this did no good. Also my edelbrock carb stumbles off idle. Please give advise to help me find the problem quickly. The 1&7 and 4&6 header tubes dont gut hot after idling for 2 min. Whats the deal? 350 motor stock.

knucklebuster · 05-25-2003, 09:24 PM

sounds like a timing problem.Do you have hei?

ddsmith · 05-25-2003, 09:42 PM

Is this a dual plane setup? It sounds like you have the one plane running rich causing low temps on the headers feed from this plane. I would suggest removing the air cleaner and start the engine then look into the air horn and see if one side of the carb is flowing liquid gas into the manifold. It may be the idle mixture screw causing that side to run rich.

shortbed70 · 05-26-2003, 12:04 AM

yes it does have hei and a duel plane intake so tomarrow I'll mess with the mix alittle.

**COBALT** · 05-26-2003, 01:07 AM

Improper metering may be your problem. I have stock metering rods and jets in my new 1406 and I've adjusted everything including timing. My next thing is to go one step leaner both on idle and cruise for the meters and jets.

shortbed70 · 05-26-2003, 01:42 PM

I got to looking and at idle the carb1406 on the pass. side it drips fuel. How can I correct this? I've got 3 1406 carbs but 2 have brocken base plates. Can I swap the top of another on to the one thats on the truck now?

05-25-2003, 09:20 PM	#1
shortbed70 Registered User Join Date: Mar 2002 Location: Forney TX Posts: 4,512	Hesitation and rough idle The truck runs good down the highway but has a rough idle. I just changed plugs but this did no good. Also my edelbrock carb stumbles off idle. Please give advise to help me find the problem quickly. The 1&7 and 4&6 header tubes dont gut hot after idling for 2 min. Whats the deal? 350 motor stock. __________________ Troy 1965 Chevy Bagged,361 sbc,voodoo cam,1.5 full roller rockers,patriot 185cc vortec heads 2.02-1.60,vortec weiand polished intake,demon carb my truckhttp://67-72chevytrucks.com/vboard/s...d.php?t=332884 Big Red Dog build http://67-72chevytrucks.com/vboard/s...d.php?t=572274

05-25-2003, 09:24 PM	#2
knucklebuster Failure is NOT an option! Join Date: Feb 2003 Location: greenwood s.c. Posts: 811	sounds like a timing problem.Do you have hei? __________________ House payment or truck parts?????.........why does life have to be so complicated? 1969 Chevy Shortbed Fleetside 1969 Camaro ps pb a/c(drove in high school now it's just a yard ornament,but it's next on the list for resto) 1990 Ni$$an hardbody( daily beater that has been really beaten!) 1999 Grand Am GT(wifes ride...never buy a pontiac!!Trust Me)

05-25-2003, 09:42 PM	#3
ddsmith Glowing since 1978 Join Date: Mar 2001 Location: Lusby,MD,USA Posts: 532	Is this a dual plane setup? It sounds like you have the one plane running rich causing low temps on the headers feed from this plane. I would suggest removing the air cleaner and start the engine then look into the air horn and see if one side of the carb is flowing liquid gas into the manifold. It may be the idle mixture screw causing that side to run rich. __________________ 66 Chevy C30 Stakebody Dump, PS,PB, 327cu in 71 Corvette Coupe 454 4 speed 69 Chevy C20 Custom Camper

05-26-2003, 12:04 AM	#4
shortbed70 Registered User Join Date: Mar 2002 Location: Forney TX Posts: 4,512	yes it does have hei and a duel plane intake so tomarrow I'll mess with the mix alittle. __________________ Troy 1965 Chevy Bagged,361 sbc,voodoo cam,1.5 full roller rockers,patriot 185cc vortec heads 2.02-1.60,vortec weiand polished intake,demon carb my truckhttp://67-72chevytrucks.com/vboard/s...d.php?t=332884 Big Red Dog build http://67-72chevytrucks.com/vboard/s...d.php?t=572274

05-26-2003, 01:07 AM	#5
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Improper metering may be your problem. I have stock metering rods and jets in my new 1406 and I've adjusted everything including timing. My next thing is to go one step leaner both on idle and cruise for the meters and jets. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

05-26-2003, 01:42 PM	#6
shortbed70 Registered User Join Date: Mar 2002 Location: Forney TX Posts: 4,512	I got to looking and at idle the carb1406 on the pass. side it drips fuel. How can I correct this? I've got 3 1406 carbs but 2 have brocken base plates. Can I swap the top of another on to the one thats on the truck now? __________________ Troy 1965 Chevy Bagged,361 sbc,voodoo cam,1.5 full roller rockers,patriot 185cc vortec heads 2.02-1.60,vortec weiand polished intake,demon carb my truckhttp://67-72chevytrucks.com/vboard/s...d.php?t=332884 Big Red Dog build http://67-72chevytrucks.com/vboard/s...d.php?t=572274

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