As far as the xt-7 engine, I have no complaints. When I bought I felt like I was taking a chance, but have been happy. I probably have 100 hours on the engine. So far I changed the oil after 5 hours. It sat in cold storage for 5 months so I replaced the plug, air and fuel filter, started on the first pull. I make sure I balance the blade well and the engine runs smooth, not a lot of vibration. So no problems so far.