Small Engines (Lawn Mowers, etc.): Briggs and Stratton 8HP 12E114-0268-E1, briggs and stratton, starter fluid

Question
HI, my engine will not stay running.  I spray engine start, and it starts, but when the fluid is used up it dies. W/o using starter fluid it does not start.  I replaced carb with one from identical unit that threw a rod, but did not have any running issues.  I am missing something but can't figure out why.

Answer
Are carburetor linkages connected properly?  Do you know if the carb is getting fuel?  Some tanks have an on/off  fuel valve and I have also had a bad gas cap or two which would not vent correctly leading to fuel not reaching the carb.

Let me know if you find a on/off fuel valve.

Eric