Now a question for Bobbin Nail and husband.
Does the engine part run and it does not make electric that works?
Or does the engine not run or starts and quits?
If it is the first, call around to shops that repair electric motors. The machine attached is just an electric motor being pushed. (OK, it may have so controls, but they should still understand what they are.
If it is the second, then call small engine shops. Onan engines are used on many small things like the giant mowers and little diggers.
Good Luck.
Matt