Was that running on starter fluid? I agree, sounded like it ran out of gas -- if the fuels bowls had been full when you started it would have run longer than that. Easy enough to check/rebuild/replace the mechanical pump and once working tend to be long-lived. I always carry a simple cheap low pressure generic electric fuel pump as a get-me-home spare, but it is also useful for initial start-up of long-dormant engines.
I agree, the engine sounded pretty good.