[nightstaker2400]

Just purchased a new Holley Brawler 600 CFM carb with vacuum secondaries and electric choke in my 283 (bored out to a 301). Cab it set to factory specs, however engine is running rich at idle, and also after it gets warmed up. Any one have a solution?

 

[Stroker Ace Ventura]

Carburetor Tuning And Adjustments - Holley Motor Life

View Carburetor Tuning And Adjustments Articles

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Here Is The Correct Procedure For Setting An Optimized Idle Mixture And Speed

Setting the idle mixture and speed on a carburetor isn't the most exciting or elegant subject, but it is a necessary adjustment that often is overlooked or worse, set up incorrectly. Here's the proper way to handle this basic task.

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Gotta get the idle air mix set first... Everything else is irrelevant at idle. If you have rich conditions off-idle, that's a tuning issue and you'll need to do your homework. No magic pill, just learning how the carburetor works is the first thing and figuring out what your engine needs to run properly, including insuring your ignition is in tip-top shape with good new plugs and that your timing is set properly for your engine combination./ If not, you're just throwing darts in the dark....

 

[nightstaker2400]

Thanks, I'll start at square one and go from there

 

[drm101]

I'd guess the link that Andy provided will get you in the ball park, but here's another little bit of info. One quick, easy check if the engine is running fat, is to turn the idle screws in one at a time and make sure the engine rpm drops. If it doesn't, you need to turn the idle speed screw to lower the rpm (close the throttle) some because the transfer slots are being exposed to much, causing the rich condition. You can also advance the timing a bit which will raise the rpm, then turn the idle speed down. Too much advance can push you into detonation or hard starting when hot, so be careful there. Check the instructions that came with the carb. Sometimes they give a spec for the minimum transfer slot exposure. You can adjust that with the carb off the car. Let us know how it goes.