Started my freshly field overhauled O-200 for the first time, today. Engine is in a C150. The engine has a scatter miss below 1200 RPM. Is the same on either mag. Mixture setting makes no change. Both mags were oh'd. Carb was oh'd with latest float and nozzle. Above 1200 RPM it is smooth with 50 RPM mag drops. Almost feels though one cylinder is not firing all the time. Sticky valve ? Have not run above 1500 RPM.
Has new Millenium cylinder assemblies. Whada ya think ?