I just recently bought a new os 61FX. When i close the carb a small crack opens up in the corner, is this normal? It only shows when there is less than a milimeter gap left, and as it closes a less than a mm slit will open on the side that the low speed needle adjustment is located. Do i need to return this or is it perfectly normal? I had a 60FP before and i never saw this on that engine.