Small Engines (Lawn Mowers, etc.): B&S 3hp rototiller stalls once warmed up., vapor lock, rototiller

Question
Runs good for 4 min then stalls. Let cool all the way and it will run for another 4 min. Fuel is good, plug is good. I placed a piece of sheet metal between exhaust and carb to reduce chances of vapor lock but it does not seem to make a difference.  

Answer
 Hello Erich:

 I take it that you cant restart the engine until it cools off. Does the Engine have Spark after it stalls. If no, then your problem is the Ignition Module (magnetron). If yes, then check the Valves for proper Valve Lash. Hope this Helps.

 Good Luck

 Respectfully

 John