There is a fault. What it is cannot be seen from here.
__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
First verify that this is a Kango that wants 240V and not 110V. (no location given so can't guess that one) I'm assuming it's 240V you need, trying the 110V output was a nice bit of jungle engineering logic if it is.
That genset should be able to do a 4000W load and have 240V output. (I googled that so it must be true)
So at risk of stating the obvious, there's something wrong in the 240V part of it.
Have you checked all fuses and/or circuit breakers yet? Do you have a manual? What tools do you have (other than the kango hammer)
Could be anything from a gecko in the alternator to a wallabied regulator.
__________________
Difficulty is not an obstacle it is merely an attribute.