Why does your Briggs and Stratton Quantum 6.0 HP Lawn mower engine keep shutting off?

When the engine shuts off, remove the spark plug and unspect it. If there is fuel on the plug, the engine shuts off because of over flooding probably caused by a clogged air filter or faulty spark plug or may need a carburetor adjustment. If the spark plug is dry, the engine shuts off due to fuel starvation caused by a clogged fuel filter or may need carburetor adjustment.