1976 Rochester problems
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
1976 Rochester problems
I am trying to set up a rebuilt carburetor on my 1976 L-48 automatic. I can get the car to idle around 1,000 but if it starts to want to die unless I give it a bit of gas to keep it going.
I just tried to keep it going to make adjustments by having it running at 1500rpm. I turned the idle mixture screws but they didn't affect it at all.
Should I take it apart and check everything or is there something that I am possibly missing?
I just tried to keep it going to make adjustments by having it running at 1500rpm. I turned the idle mixture screws but they didn't affect it at all.
Should I take it apart and check everything or is there something that I am possibly missing?
Le Mans Master
Joined: Oct 2010
Posts: 6,915
Likes: 836
From: melbourne florida
2023 C3 of the Year Finalist - Modified
you need to have the Carb gone through by someone competent with quadrajet carburetors. i ended my battle by installing a Holley. i know there is a big q jet fan club on here but I'm much more pleased with a Holley.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Who knows,..could be anything from wrong float setting to stuck power piston (in the up position) to cracked body.
Since you're able to get another carb to idle fine, I agree with you; it has to be your new 'rebuilt' carb.
How familiar are you with q-jets? If so, take it apart and see if you can find something. One thing to look for is a warped air horn caused by the front carb mounting bolts over-tightened through the years. This causes plenty of problems especially at lower RPMs and idle.
Does it leak anywhere? I assume your choke is correctly set. I also assume the correct kit was used for rebuild. You may want to note the carb's number then take it to your favorite parts counter and order up a new kit; one you know to be correct. Standard or Federal make good q-jet kits.
Thinking out loud here,..again, it could be a lot of things.
Since you're able to get another carb to idle fine, I agree with you; it has to be your new 'rebuilt' carb.
How familiar are you with q-jets? If so, take it apart and see if you can find something. One thing to look for is a warped air horn caused by the front carb mounting bolts over-tightened through the years. This causes plenty of problems especially at lower RPMs and idle.
Does it leak anywhere? I assume your choke is correctly set. I also assume the correct kit was used for rebuild. You may want to note the carb's number then take it to your favorite parts counter and order up a new kit; one you know to be correct. Standard or Federal make good q-jet kits.
Thinking out loud here,..again, it could be a lot of things.
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Who rebuilt the Quadrajet? A very common theme on here by those that know Quadrajets is that many rebuilds come with a real hodgepodge of pieces in them. One thing for sure about the Quadrajet is it doesn't respond well to this type of rebuild.
These folks "wrote" the book (literally) on Quadrajets and if you follow their guidance you won't be far off.
http://www.cliffshighperformance.com/
I am no expert on Quadrajets, but I've rebuilt my fair share of Holley's, Quadrajets and FOMOCO's over the years. I would call myself a competent rebuilder vs. an expert. Never-the-less I've always managed to make the Quadrajets run just fine. I'm guessing this may be why the experts like them so much.
Good luck... GUSTO
These folks "wrote" the book (literally) on Quadrajets and if you follow their guidance you won't be far off.
http://www.cliffshighperformance.com/
I am no expert on Quadrajets, but I've rebuilt my fair share of Holley's, Quadrajets and FOMOCO's over the years. I would call myself a competent rebuilder vs. an expert. Never-the-less I've always managed to make the Quadrajets run just fine. I'm guessing this may be why the experts like them so much.
Good luck... GUSTO
