Hi I have a yard king self propelled mower (not riding) that is about 4 years old. At the end of last year it began having a problem where - it would start up and run great - but as soon as it got warmed up (about the time of the first bag dump) it would not restart. Sometimes if I shook it as I was pulling the start cord it would sputter back to life and run great but then the same problem whenever it was shut off again. As soon as the engine would cool down it would start fine. It is a B&S motor. Not sure of the model number but was just wondering if anyone has encountered something like this. Thanks.

Could be the coil overheating and separating. You may have to replace the coil.