Carburetor trouble - The 1947 - Present Chevrolet & GMC Truck Message Board Network

djfugate · 03-21-2013, 10:30 PM

I have a 1970 Chevy C10 p/u with a 2 wheel drive, 350 engine w/quadrojet carburetor. I am having trouble adjusting the carburetor. Can anyone help?

**truckster** · 03-21-2013, 10:48 PM

Can you be more specific? What kind of problems are you having?

djfugate · 03-21-2013, 11:00 PM

popping in the carburetor on acceleration

Crabass · 03-25-2013, 06:33 PM

Do you know the carb's history, that is, do you know if it is all original, or replacement? Does it have the original greenish goldish finish, or has it been blasted? Does it have a remanufacturer's sticker on it?

If it is all original you are ahead of the game. The QJ is a very application specific, complicated critter, and you really have to know your stuff to competently troubleshoot/repair them. They've gotten a bad rep in the past due to things done to them that shouldn't have been, even by those that supposedly were knowledgeable pros. What is the number on the carb? (It reads vertically about the middle of the drivers side secondary.)

If your carb is original I'd stick with it if I were you. If you do I highly recommend getting at least one good book on the subject. The one by Cliff Ruggles would be a good start.

Sounds to me like you might have lean misfire. It's always a good idea to make sure your ignition system is right before you start playing with the carb.

**Ol Blue K20** · 03-25-2013, 07:44 PM

Or a floating exhaust valve

GASoline71 · 03-25-2013, 07:49 PM

Could also be timing. Make sure your timing is nailed down before troubleshooting a carb.

Gary

68gmsee · 03-25-2013, 08:24 PM

Good advice by all above.

Study as much as you can on it before digging into it and giving it a good cleaning and installing a kit in it. There's a lot of good reading on the net and even on youtube.

But, first check all the easy stuff starting with exhaust leaks and vacuum leaks. Check around the base mounting gasket for leaks. Ignition timing and ignition components as mentioned above are also an easy check. If plugs or points are bad you may get popping or misfiring in the exhaust.

Other things that can get a little more difficult are bad valves and on high mileage small blocks of the early era, is a worn camshaft.

Aaron Burkemper · 03-25-2013, 11:34 PM

Ignition timing or weak ignition system can share these symptoms. Try checking the timing, and a good tune up never hurts.

03-21-2013, 10:30 PM	#1
djfugate Registered User Join Date: Jan 2008 Location: san bernardino Posts: 4	Carburetor trouble I have a 1970 Chevy C10 p/u with a 2 wheel drive, 350 engine w/quadrojet carburetor. I am having trouble adjusting the carburetor. Can anyone help?

03-21-2013, 10:48 PM	#2
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,869	Re: Carburetor trouble Can you be more specific? What kind of problems are you having?

03-21-2013, 11:00 PM	#3
djfugate Registered User Join Date: Jan 2008 Location: san bernardino Posts: 4	Re: Carburetor trouble popping in the carburetor on acceleration Last edited by djfugate; 03-21-2013 at 11:24 PM.

03-25-2013, 06:33 PM	#4
Crabass Registered User Join Date: Nov 2006 Location: Virginia's Eastern Shore Posts: 91	Re: Carburetor trouble Do you know the carb's history, that is, do you know if it is all original, or replacement? Does it have the original greenish goldish finish, or has it been blasted? Does it have a remanufacturer's sticker on it? If it is all original you are ahead of the game. The QJ is a very application specific, complicated critter, and you really have to know your stuff to competently troubleshoot/repair them. They've gotten a bad rep in the past due to things done to them that shouldn't have been, even by those that supposedly were knowledgeable pros. What is the number on the carb? (It reads vertically about the middle of the drivers side secondary.) If your carb is original I'd stick with it if I were you. If you do I highly recommend getting at least one good book on the subject. The one by Cliff Ruggles would be a good start. Sounds to me like you might have lean misfire. It's always a good idea to make sure your ignition system is right before you start playing with the carb.

03-25-2013, 07:44 PM	#5
Ol Blue K20 Proprietor of Dale's Corner Join Date: Nov 2012 Location: Vacaville , CA Posts: 15,955	Re: Carburetor trouble Or a floating exhaust valve __________________ "Some Days Chickens And Some Days Feathers" Dale XNGH ECV Sam Brannan 1004 R.I.P. 67ChevyRedneck R.I.P. Grumpy Old Man

03-25-2013, 08:24 PM	#7
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Carburetor trouble Good advice by all above. Study as much as you can on it before digging into it and giving it a good cleaning and installing a kit in it. There's a lot of good reading on the net and even on youtube. But, first check all the easy stuff starting with exhaust leaks and vacuum leaks. Check around the base mounting gasket for leaks. Ignition timing and ignition components as mentioned above are also an easy check. If plugs or points are bad you may get popping or misfiring in the exhaust. Other things that can get a little more difficult are bad valves and on high mileage small blocks of the early era, is a worn camshaft. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

03-25-2013, 11:34 PM	#8
Aaron Burkemper Registered User Join Date: Sep 2011 Location: New Melle, MO Posts: 104	Re: Carburetor trouble Ignition timing or weak ignition system can share these symptoms. Try checking the timing, and a good tune up never hurts. __________________ 1971 C20 "Shreck" 1980 C30 dump bed "Ratchett"



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