We were using our ODB leaf loader last evening when all of a sudden a load backfire came from the engine and it stopped. We have been unable to start it since. I took it to our local Kawi service center and they tested it for fire...none to be found. They are going to get into it further today.... I was told it could be the flywheel key?? Me not being too mechanically inclined...was wondering about that.... Any input or opinions????