502 bogging
#1
502 bogging
i have a 502 with a quadrajet i get it up to right about 400 rpms and it bogs down if you give it a little more throttle. if you continue to throttle it up more you can get it past the bog and to 4200 4300 rpms and up to 5000 with no bogging. Does anyone have any idea what could cause this? Metering rods, secondaries not opening soon enough? thanks for any help
#2
Fast Singles Club
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i have a 502 with a quadrajet i get it up to right about 400 rpms and it bogs down if you give it a little more throttle. if you continue to throttle it up more you can get it past the bog and to 4200 4300 rpms and up to 5000 with no bogging. Does anyone have any idea what could cause this? Metering rods, secondaries not opening soon enough? thanks for any help
#4
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Sounds like maybe dirt or varnish in the primary circuit . Take the lid off and hit those circuits with carb cleaner then blow it out with air . Did it set with untreated fuel for awhile ?? Also make sure acc pump is pissing two strong streams of fuel not weak or dribbling . Does it idle ok in and out of gear and at what r.p.m. Make sure you have no vacuum leaks . A faulty choke pull off can also cause this .
Last edited by the deep; 04-23-2012 at 10:28 PM.
#5
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502 with a quadrajet continue to throttle it up, to be frankly , not understand .sorry .
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#7
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Just a suggestion , you may be happier with a Holley 800 for that 502 . Take the numbers off your Quad , they are located on the port side right above the secondary linkage and lets see what engine it came off of .
#8
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There is a torsion spring that preloads the air valve (butterfly) on the top of the carb for the secondaries. If it is set too lightly the air valve will open too soon and lean it out causing a bog. There is an ajustment screw up under the top plate that is used to adjust this to get the bog out. If I remember right you adjust the screw until it just starts to tension the butterfly then go another 1/2 turn on the screw. Then you adjust it from there to fine tune the bog away.
#10
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adjust air valve like bluethunder said, there is setscrew from underneath. you need to loosen it while using small screwdriver to hold tension adjuster. setscrew maybe hex or torx(t10?) tighter sometimes helps, as engine airflow will pull airvalve open.