Yup, be wary. We were at a Solar Eclipse camp a month ago and our generator would not start. We have a 4000W Onan in our RV. We went down to Harbor Freight and picked up a 4000W generator on sale for $287. It only had 13A / 110VAC outlets. These would not run our air conditioner - the circuit breaker kept tripping on the genset. Fortunately we could return the generator.
And was pointed out above, even with a 110V adapter you have to be careful as with cheaper adapters they can overheat and melt from the high current pulled through them.