pelham

Check all the head and backplate bolts. Also, check the nut on the high end neddle. It sounds like you may have an air problem. go with the lower prop. I have been flying for years and the Super Tigres are great engines. I do not think anyone was calling you an idiot, rather trying to help. I have a Super Tigre in an 60 size 300 Extra and get around 15 K. The engine should performe better than that. Why return it, get what you paid for. That is what the warranty is for.