Repairing a Honda EB6500x generator. Electronic ECM. Motor was seized and required extensive parts to get rebuilt. New block, piston, rod,rings, head, valves, pushrods,etc. It runs and makes power but it has a bit of a stumble at full speed with noticeable pops from the muffler. At idle on auto throttle it surges quite a bit. I've been through the carb three times to make sure it's all good and checked valve clearance. Checked pilot jet and pilot screw, all good. Still running rough. I completely removed the pilot screw while it was running and the engine ran perfectly smooth. That's the tiniest passage and removing the screw would be adding more air to the mix, right? My only other thought is that it could be a tooth or two out of time in the crankcase? Would it even run at all if that was the case? Any help is appreciated.