Small Engines (Lawn Mowers, etc.): runs but turns off, briggs stratton, seat drop

Question
I have a briggs & stratton 5.0 hp mower.After it starts it shuts off.New plug,fresh gas running yesterday.

Answer
check  for water or dirt in fuel bowl  of carb. clean it out.  check for needle and seat drop under float. check for fuel  restrictions to carb. for slow flowing fuel to carb.  and as a last  check>  as soon as it shuts down  check for fire at plug, if none? but you wait a bit and it cools down and there is again?  your firing coil is shot.  it shorts out, and after it sets fires again.