how to clean up the idle circuit on a 8896 dominator carb.
 

i have a 572 bbc 9.7-1 comp, roller cam 114 lobe sep, dart 34 heads. The enngine was built and dynoed by ohio crankshaft. Evidently they paid no attention to the idle cause it blackens the plugs after idling a bit and then fouls them. Engine runs good except for the idle. It was built for a inboard outboard boat and has to idle at 850 to shift into gear without banging. I have tried drilling out the idle air bleeds a couple of times , but still idles to rich. Also the exhaust runs under water while idling and once on plane it is straight out the back. 5 inch exhaust tips with 2 1/8 id exhaust tubes water jacketed by lightning. Please help with what to do to clean up the idle.

look down the carb and see if the butterflies are closed or if there are open enough to pull fuel from the idle transfer slots.if there open you need to drill or enlarge the bypass holes in the butterflies one step at a time until your idle speed is what you want with the butterflies almost closed. at this point you shouldn't be pulling fuel from the transfer slots and should be able to adjust the idle mixture as lean as you want.Bill

what are the transfer slots for in the carburetor
 

how do the transfer slots work in a carburetor

when the throttle blade is opened and vacuum is present it pulls fuel from the transfers , these are responsible for partial throttle opening, there should be 3 or 4 in a row, then after the throttle is cranked wide open the bolsters flow most of the fuel needed.
close both primary and secondary and open the primary just untill the car will idle, then open the secondary till the idle increases slightly, they should both be pretty much at the same opening at that point.
having one open too much will cause an overly rich idle and bad response.
Al