I say get a better tech! Did he specify what the problem was? I'm guessing that he didn't
It is almost impossible to destroy an Onan after only 220 hours!! Onans have a built in low oil pressure switch to protect the engine, and oil pressure is just about the ONLY thing that could cause "internal issues" in a engine with so few hours! I am no expert by any means, but it is certainly worth your peace of mind and usefulness of your RV to have that generator looked at by a competent tech! More than likely, it'll be the usual problem of a gummed up carb, or a bad control board, both ~$500 repairs!
Good luck:)
