Taking A Long Time To Start

Hello, I have a Snapper 33" LT140HBBV with a B&S 14hp model#287707. Problem is the mower is taking a very long time to start, I have to crank it for 20+ seconds. When it catches it will make a few loud bangs and put out a big puff of smoke. Once it is running it sounds fine and will start immediately once it is warmed up. I did adjust the valves over the weekend but it didn't seem to help, it actually seems to take a little longer now. I thought maybe it was a choke problem so I watched the levers as I moved the throttle up and it is hitting the choke. I didn't verify that it was moving at the carb though. Not sure what to try next, any suggestions? Also, I verified the fuel filter is good.

Thanks,
Chris