Need help with Quadrijet 4-barrell - The 1947 - Present Chevrolet & GMC Truck Message Board Network

seth69c10 · 03-30-2002, 05:51 PM

I have a 305ci motor in my 69 C-10, and I think that I have a problem with my Quadrijet carburator. I don't think that the 4-barrell is kicking in. If I am going down the road at 30-40 mph and I floor it, I feel or hear nothing. Now I know that a 305 won't throw me back in the seat, but shouldn't I feel something or at least hear the 4-barrell roaring?

Thanks for the help
Seth

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1969 C10
SWB, stepside, p/s
rebuild completed

Benrs86 · 03-30-2002, 06:54 PM

you should definately feel it, at least i could with my quadrajet. it is easy to fix. go to your parts store and ask for a perfromer intake and a 1406 carb. that is a AWESOME setup. i have had mine for 8 months now and have hardly adjusted a thing. WAAAAAAAAAAAY more powerful. i love it. good luck, Ben

O'l Buck · 03-30-2002, 07:10 PM

check the adjustment on the secondary linkages, vacuum diaprhagms etc. you may be opening the throttle plates, but not the butterflys. You can check it by looking down inside the secondaries holding the butterflys open and opening the throttle to wide open. Your pedal linkage may be out of adjustment too.

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'72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

67 Cutlass convertible
330, 3spd stick

90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

**truckster** · 03-30-2002, 09:14 PM

Your quadrajet is probably just needing a little adjustment. The Q-Jet is a great carb, and will make a ton of power if set up properly. It's dependable and I wouldn't trade my 800 cfm Q-Jet for any aftermarket carb.

Assuming the carb is not fouled (they're easy to rebuild), I'd look at the choke pull-off and the air valve spring adjustment. On my 455 I had the air valve spring set to open right off idle, but you probably want to adjust it for good economy as well as power. Here are links to a couple of good articles on adjusting the Q-Jet:
http://www.hotrodding.org/enginetech13.html
http://vetteworks.tripod.com/Qjet.htm

Project1970 · 03-30-2002, 10:47 PM

The choke flaps might not be opening up when it warms up...when it's in a cold condition, you can't get the secondaries open. If it's not set right, they might not open no matter how hot it gets.

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Project 1970 - soon to be seen at http://milhouse.treylis.org:81/

seth69c10 · 04-02-2002, 01:55 AM

Thanks for the help!!
Any more suggestions?

03-30-2002, 05:51 PM	#1
seth69c10 Registered User Join Date: Jun 2001 Location: Conway, Arkansas Posts: 16	Need help with Quadrijet 4-barrell I have a 305ci motor in my 69 C-10, and I think that I have a problem with my Quadrijet carburator. I don't think that the 4-barrell is kicking in. If I am going down the road at 30-40 mph and I floor it, I feel or hear nothing. Now I know that a 305 won't throw me back in the seat, but shouldn't I feel something or at least hear the 4-barrell roaring? Thanks for the help Seth ------------------ 1969 C10 SWB, stepside, p/s rebuild completed __________________ 1969 C10 SWB, stepside, p/s rebuild completed

03-30-2002, 06:54 PM	#2
Benrs86 Registered User Join Date: Feb 2000 Location: Brandon, SD, USA Posts: 1,292	you should definately feel it, at least i could with my quadrajet. it is easy to fix. go to your parts store and ask for a perfromer intake and a 1406 carb. that is a AWESOME setup. i have had mine for 8 months now and have hardly adjusted a thing. WAAAAAAAAAAAY more powerful. i love it. good luck, Ben __________________ Brandon, SD 69 GMC 1/2 ton 2wd wide long bed with wood 3 on the tree 350 engine 4 bolt main rv cam AIM = Alphray04

03-30-2002, 07:10 PM	#3
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	check the adjustment on the secondary linkages, vacuum diaprhagms etc. you may be opening the throttle plates, but not the butterflys. You can check it by looking down inside the secondaries holding the butterflys open and opening the throttle to wide open. Your pedal linkage may be out of adjustment too. ------------------ '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84 ralleys and 31/10.5s 67 Cutlass convertible 330, 3spd stick 90 GMC Jimmy 350/auto Chad Stephens Orleans,NE __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

03-30-2002, 09:14 PM	#4
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,856	Your quadrajet is probably just needing a little adjustment. The Q-Jet is a great carb, and will make a ton of power if set up properly. It's dependable and I wouldn't trade my 800 cfm Q-Jet for any aftermarket carb. Assuming the carb is not fouled (they're easy to rebuild), I'd look at the choke pull-off and the air valve spring adjustment. On my 455 I had the air valve spring set to open right off idle, but you probably want to adjust it for good economy as well as power. Here are links to a couple of good articles on adjusting the Q-Jet: http://www.hotrodding.org/enginetech13.html http://vetteworks.tripod.com/Qjet.htm __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

03-30-2002, 10:47 PM	#5
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	The choke flaps might not be opening up when it warms up...when it's in a cold condition, you can't get the secondaries open. If it's not set right, they might not open no matter how hot it gets. ------------------ Project 1970 - soon to be seen at http://milhouse.treylis.org:81/ __________________ Project1970 - LS1 Swap Complete!

04-02-2002, 01:55 AM	#6
seth69c10 Registered User Join Date: Jun 2001 Location: Conway, Arkansas Posts: 16	Thanks for the help!! Any more suggestions? __________________ 1969 C10 SWB, stepside, p/s rebuild completed



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