this is a newer john deere D105 tractor 17.5 hp 42" deck . this was purchased in May 2013 . before taking it to dealer for warranty work I want to see if I can fix myself first. i just mowed the lawn yesterday and ran fine. i go to try and start it today and it just kicks over on choke and dies right away. i know the seat sensor , i know the brake has to be pushed. ive tried put everything in every position. i then thought it was fuel because the filter has like nothing in it . so i disconnected going into carb and cranked. it was pumping fuel fine. now im thinking is it the sensor in the bottom of the float bowl or another sensor went bad? any ideas?