I have a 4053 holley on my 396/375 nova with the stock solid cam .the problem is I cannot get the car to idle down below 1300rpm ,once you adjust the idle mixture screws in and out the car eventually idles down and shuts/off( very difficult to set the mixture screws}.sometimes when you shut the car off it pops back through the exhaust;which I would guess there is too much gas in the cylinder with the mixture problems of the carb,thanks for any help.Chris
Try opening up the secondary throttle blades. The front throttle blades should be about .030" into the transfer slot at idle. Other than that, you may have a clogged passage, leaking booster, etc. I also have seen alot of carburetor problems repaired by fixing the ignition system. :grin: Have fun.
Chris; What you're describing sounds like a dirty idle circuit. I'm assuming that since you can't get it to idle down below 1300 rpm that the idle trim screws aren't having much effect? Try this: With the choke in the fully open position (so the primary throttle isn't resting on the fast idle cam), back the curb idle screw completely off until the primary blades are completely closed. Then slowly turn the curb idle screw back in until it just starts to nudge the throttle shaft, then go down 1 1/2 turns more. This is to baseline the curb idle adjustment. Next, remove each trim screw from the primary metering block one at a time, making sure not to lose the small cork seals. Take some aerosol carb cleaner and give the trim ports a good blast using the little plastic hose that came with the carb cleaner. You should see a stream of carb cleaner shoot up out of the choke tower from the idle air bleeds. Then take an air hose and blast the trim ports a good blast. Again, you should see carb cleaner shoot up out of the choke tower. This should dislodge any debris that may be clogging the idle circuits. Re-install the trim screws and the cork seals making sure not to cross-thread them, and run them in until they lightly bottom out. Then back each one out 1 1/4 turns and start the engine to see if that helped or not. If it doesn't help, let me know and I'll try to help. BTW, yes, I'm a "newbie" here and this is my first post on this forum; I mainly post over at the yenko site under the username "VintageMusclecar". As far as my advice above, I restore carbs for a living so I know my way around them pretty well. Eric
Eric is right. the cat pee gas that we get now days will clog a carb up. A carb is not designed to work with any contaminate in it. If the engine would idle at lower rpm before then it will again. just stay with it untill you get it whipped.
