does not stall in drive while the choke is still on? might be as simple as going more CCW on the idle mixture screws to richen the idle. Not sure if float setting affects idle A/F but are they set correct? I'm assuming initial and idle speed are in the ballpark. blasting a 3 second shot of brake kleen into each idle mixture port may help & if it does (by itself) then for sure get a good filter on there right before the carb inlet. just some stuff to try