Yes it has a hard start cap, and as I have said it starts just fine and can run for a long time without an issue, even at a high load. Once an A/C unit is running the start capacitor is no longer in play. The A/C staring is by far the biggest amp draw and it will start with the fridge on, converting pushing 30A, and other AC loads without issue.
I've been using it in these conditions for years, something isn't working right. The generators are barely above idle and then they go to max load.
Peak output is 4000w is parallel mode. The reduction for altitude is in horsepower and if the generator is able to rev up and trip the overload circuit it has enough horsepower to make full power. When a generator is horsepower limited it won't be able to trip overload as the rpms won't allow for it. It's not a ambient conditions issue. It's an output or an A/C issue.
I'm considering ordering a run capacitor.