Re: Proper carb adjustment for Rochester BC
Start with a warm engine and get an idle speed of about 850 rpm. Then adjust idle mixture by screwing in mixture screws one at a time until you get a slight lean drop and you reach 750 rpms after you adjust both screws. This will help prevent that black soot line on your transom.<br />There is an adjustment for the restrictor plate if you have a 4 bbl, but you don't mess with that unless you have a performance problem. <br />Choke is adjusted with the engine cold. Adjust the tension on the flap by inserting a 3/16" drill bit between the flap and the horn and adjusting spring tension to hold the flap at that point when the throttle activates the choke. If the carburetor has a fast idle screw, that should be set at 1500-2000 rpms cold. <br />This should get you started. You may find it idles and shifts better slightly richer, or maybe slightly leaner. Choke can be adjusted tighter, but pull off becomes a problem if its too tight.<br /><br />Dont forget to check wide open throttle position, flaps should be all the way open.
