Mike:
That generator is rated at 6000 Watts surge. If I'm doing my math right that translates to about 7.25Hp and that's the absolute max. However before you start thinking that will run anything you've got, remember that when starting, a motor will pull about 6 times its' full load amps. So effectively you'd be able to start about a 1.25Hp motor, anything larger and I think you might run the risk of damaging something. You could probably run several motors of that size, just start them individually and watch the meters on the generator to keep it in the green.
I remember that many years ago when we lived on the farm we had a 20KW alternator powered by the tractor's PTO. We could run three 5Hp motors at the same time, as long as we didn't push them too hard.. But they had to be started separately and let come up to speed before we tried starting the next one. At least it let us run the vacuum pump for the milkers, the auger on the feed bunk, and the silo unloader at the same time so we could get the milking done and feed the cows.
Don