There has to be a breaker or fuse somewhere in the generator. More than likely the shop vac was too large of a load. There MUST be an overcurrent device somewhere in that generator. Have you tried to restart the engine after it died? It may have stalled out due to the overload. Try to restart and plug in a smaller load. The shop vac uses too much current for that size of a generator. A rule of thumb for loading is volts times amps equalls watts.