How did the engine start prior to changing the carburetor???
Weak ignition is the culprit as often (maybe more so) as a defective carburetor. If the ignition is defective, changing or adjusting the carburetor will not help the ignition. I have solved many "carburetor starting issues" by hooking a jumper cable from the ground terminal of the battery to a wire-brushed head bolt
Chokes were put on carburetors for a reason.....to aid in cold starting and help atomize the fuel prior to the engine acquiring normal temperature. As Jerry stated, an engine that will start cold without the aid of the choke is way too rich, and costing fuel economy, possibly even doing damage to the engine.
Carburetion 101 - there are three ways to improve the atomization of fuel: (1) heat, (2) air velocity, and (3) additional fuel i.e. choke.
Jon.
