Edelbrock carb

[Moparsmitty]

Yesterday I was tuning on the Belvedere because it was idling a little rough. One of the things that I did was take out the idle mixture screws on the 750cfm Eddy I'm running and shoot some carb cleaner into the ports followed by a blast of air. The points on the mixture screws looked good with no apparent damage. Put the mixture screws back in, carefully bottomed them, and backed them out two turns. Started er up and it idled good. About 800 rpm. I proceeded to fine tune the mixture for maximum vacuum. I'm getting about 13-14 Inches of vacuum. The weird thing is that I could run both mixture screws all the way in and the engine would still run. It wouldn't run well, but it would run. Shouldn't that kill the engine? I looked down the carb throat and I couldn't see any gas coming out of the boosters. I'm wondering if the carb is leaking internally or maybe it has the wrong mixture screws in it. I haven't rebuilt this carb but that might be next. Any ideas? Thanks.

 

[67 coronet]

sometimes the seats are not a perfect match and you can still have a small flow by the mixture screws,thereby letting the car still barley run.prob wouldnt hurt to rebuild it anyhow,could be some dirt stuck in there and you can check for any small cracks.

 

[rumblefish360]

I'd bet your running rich.

 

[Histoy]

Sometimes if you run a high performance cam, you have to adjust the idle speed screw in so far that the butterflies start to uncover the slots for off idle operation. If that's the case, then drill a 0.030" hole in each of the primary butterflies. This will allow some air to pass thru them, and you can back out the idle speed screw to close the butterflies, and allow the mixture screws to be adjusted normally. I've run into this problem when using the MP 509 cam.