Another Q Jet question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dion · 11-27-2002, 11:52 AM

The jets on the left hand side aren't working or are clogged, it's a brand new carb, quadrajunk? Any suggestions?

Truckstr · 11-27-2002, 12:15 PM

Brand new as in rebuilt new?

I'd say take it back and exchange it for another carb.

I've run Q-jets for years and found them to be very adjustable and good reliable carbs - if built right. Joe Average is going to have a steep learning curve if he fools with a Q-jet and in not familiar with all of the adjustments.

Holleys are easier to work on, but I like the spreadbore design of the Q-jet personally for a daily driver.

Jeff

dion · 11-27-2002, 12:23 PM

What would cause only one side of the carb to work? "Junk" clogging the jets?

ChevLoRay · 11-27-2002, 01:04 PM

I love my Q-Jet...an Edelbrock 1901.

As for saying that the "jets are clogged", how do you know? What is it doing that makes you think that?

If it is a rebuilt unit, do like the earlier post said and take it back. If you rebuilt it, you should check a few things. If it is new, take it back.

Frequently, people will feel compelled to adjust the idle air screws in the base plate. When I rebuilt one, I always gently, and I mean GENTLY, turn them in until they bottom out. If you put too much torque on them, you WILL, I repeat you WILL cut a groove in the idle air screws that will give you some grief when you try to adjust them. When I set them after a rebuild, I always backed them out about 2 and a half turns, for a reference point. You'll need a tach and a vacuum guage to help set them, if you have access to them. Otherwise, someone with an ignition analyzer, i.e., Sun Machine, can hook it up and make adjustments and check other stuff, too. like doing a cylinder balance test.

What is the carb doing that makes you think it is screwed up? I have seen times when carbs got blamed when the problem was something else......and vice-versa. Ain't nobody else to explain it better than you, so what is it doing?

dion · 11-27-2002, 01:46 PM

Well the secondaries won't open at all and one side of the carb is only giving a tiny amount of fuel.

11-27-2002, 11:52 AM	#1
dion 72 Cheyenne Join Date: Oct 2001 Location: San Diego Posts: 2,086	Another Q Jet question The jets on the left hand side aren't working or are clogged, it's a brand new carb, quadrajunk? Any suggestions? __________________ Burnout Idle 1972Cheyenne 1966/67Stouts

11-27-2002, 12:15 PM	#2
Truckstr Registered User Join Date: Nov 2002 Location: Lebanon, Tennessee Posts: 1,372	Brand new as in rebuilt new? I'd say take it back and exchange it for another carb. I've run Q-jets for years and found them to be very adjustable and good reliable carbs - if built right. Joe Average is going to have a steep learning curve if he fools with a Q-jet and in not familiar with all of the adjustments. Holleys are easier to work on, but I like the spreadbore design of the Q-jet personally for a daily driver. Jeff __________________ Jeff '67 short Fleet; my ongoing project. '66 long Fleet; my original "baby." Live life or bust trying.

11-27-2002, 12:23 PM	#3
dion 72 Cheyenne Join Date: Oct 2001 Location: San Diego Posts: 2,086	What would cause only one side of the carb to work? "Junk" clogging the jets? __________________ Burnout Idle 1972Cheyenne 1966/67Stouts

11-27-2002, 01:04 PM	#4
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	I love my Q-Jet...an Edelbrock 1901. As for saying that the "jets are clogged", how do you know? What is it doing that makes you think that? If it is a rebuilt unit, do like the earlier post said and take it back. If you rebuilt it, you should check a few things. If it is new, take it back. Frequently, people will feel compelled to adjust the idle air screws in the base plate. When I rebuilt one, I always gently, and I mean GENTLY, turn them in until they bottom out. If you put too much torque on them, you WILL, I repeat you WILL cut a groove in the idle air screws that will give you some grief when you try to adjust them. When I set them after a rebuild, I always backed them out about 2 and a half turns, for a reference point. You'll need a tach and a vacuum guage to help set them, if you have access to them. Otherwise, someone with an ignition analyzer, i.e., Sun Machine, can hook it up and make adjustments and check other stuff, too. like doing a cylinder balance test. What is the carb doing that makes you think it is screwed up? I have seen times when carbs got blamed when the problem was something else......and vice-versa. Ain't nobody else to explain it better than you, so what is it doing? __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. Last edited by ChevLoRay; 11-27-2002 at 01:07 PM.

11-27-2002, 01:46 PM	#5
dion 72 Cheyenne Join Date: Oct 2001 Location: San Diego Posts: 2,086	Well the secondaries won't open at all and one side of the carb is only giving a tiny amount of fuel. __________________ Burnout Idle 1972Cheyenne 1966/67Stouts



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