I have the last of a dying breed here and am having a little trouble with it. It's a Toro Commercial Proline mower with a Suzuki 2-cycle engine. I can get it started, but it will only run for about 5 minutes or so and then die. I then try to restart it without any luck. Yesterday I pulled the filter out so I could check to see if the choke was stuck or something. When I tried to start, a little bit of smoke came out of the carb. Any suggestions?