[Richard]

Is it possible that the broken stay at the rear of the engine is the problem? In other words, the two pipes must be in alignment and parallel for one to slide inside the other. It sounds like this slip joint is binding. Is the generator coming straight out or is it sagging at the front or rear?

It is a simple slip joint. You could force it out by tugging on it with the car, or a come along. But if the two pipes are misaligned just be aware that you WILL be fixing whatever caused the misalignment before the generator will slide back in