Hi. First post to the site. I used search but couldn't find what I was looking for. I have an Exmark Turf Ranger, 22HP Kohler engine, 60" deck. I tried to run it the other day and here's what happens: Full choke is on and starts up fine. Drop choke and it dies. If I leave the choke half on it will idle. But the minute I drop it, it dies....every time. Thoughts?