Carb problem?
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Joined: Sep 2008
Posts: 90
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From: florida
Carb problem?
My 1973 L48 4 speed is stock except for headers and removed AIR system. It runs great except when I stomp on the accellerator from a steady speed (while in an appropriate gear). When I do stomp on it, it boggs down and won't accelerate. Any suggestions?
Burning Brakes
Joined: Jun 2005
Posts: 764
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From: THE OLDER I GET THE BETTER I WAS! NORTHERN ONTARIO
There are a few things it could be...Try the search & find the topics that are similar to yours...there is a lot of good information in there...I am guessing that it could be the accelerator pump, but I'm just throwing that out there as one of the causes
Melting Slicks
Joined: Mar 2006
Posts: 2,465
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From: Orange Park Fl
Two most likely culprits (assuming this is a Quadrajet):
1. Accelerator pump: Take off the air cleaner and look down the primary (small) barrels, then pull the throttle linkage. You should see two strong streams of gas shoot into the bores. If the streams are weak, sputter or are non-existent, you need a new pump plunger (rebuild kit, cheap and easy).
2. Mal-adjusted secondary air valve: The butterfly on top of the secondary (large) barrels is the air valve that makes a Quadrajet a variable CFM carb. It's tension is adjusted by a spring on the passenger side. As you look at the air valve shaft on the passenger side, there is a small standard head adjustment screw. Directly below it (at 90 degrees) is an allen head screw that holds the adjustment. You may need a mirror to see the allen screw. As you look underneath at the allen screw you will see a spring on the shaft. You need to slightly loosen the allen screw and the as you look at the spring, turn the flat head adjusting screw 7/8" beyond the point at which the tang on the spring first makes contact with its stop pin. Then re-tighten the allen screw to hold the adjustment.
God bless, Sensei
1. Accelerator pump: Take off the air cleaner and look down the primary (small) barrels, then pull the throttle linkage. You should see two strong streams of gas shoot into the bores. If the streams are weak, sputter or are non-existent, you need a new pump plunger (rebuild kit, cheap and easy).
2. Mal-adjusted secondary air valve: The butterfly on top of the secondary (large) barrels is the air valve that makes a Quadrajet a variable CFM carb. It's tension is adjusted by a spring on the passenger side. As you look at the air valve shaft on the passenger side, there is a small standard head adjustment screw. Directly below it (at 90 degrees) is an allen head screw that holds the adjustment. You may need a mirror to see the allen screw. As you look underneath at the allen screw you will see a spring on the shaft. You need to slightly loosen the allen screw and the as you look at the spring, turn the flat head adjusting screw 7/8" beyond the point at which the tang on the spring first makes contact with its stop pin. Then re-tighten the allen screw to hold the adjustment.
God bless, Sensei
Thread Starter
Advanced
Joined: Sep 2008
Posts: 90
Likes: 20
From: florida
Thanks for your responses. This site is a great help and it's good to know of all the good people out there in the Corvette community. Sensei's point two sounds like my problem. Thanks again.
