[Big hammer]

Why is it that internal combustion engines need a higher idle when cold and the choke is closed ? When I start my A when cold #1 retard the spark,#2 hand throttle 2 clicks down,#3 gav 3/4-1 turn richer,#4 gas valve open,#5 ignition switch on,#6 pull the choke,#8 hit the starter, #7 release the choke after 2-3 turns and then it starts. IF it doesn't start after trying 2X I look at the points check the gap and or clean the points. IF it starts and then dies I check to make sure that I've not forgotten to open the gas valve ( it happens)

Your idle issue; after its warmed up #1 retard the spark lever, #2 close the gav,#3 adjust the idle speed to a nice slow speed as to not die,#4 then adjust the idle air screw in and then out finding a middle ground to where it runs smooth. If after this you still cannot get it running with out backfiring you may need to go though your carburetor .