.......closing the carb right before "ground zero" does wonders .
GaRcfield, If you've pulled the engine this far apart, a good rinsing at the sink with hot soapy water is an excellent treatment. Follow up with BrakeClean solvent and a compressed air blow out. Turn the bearings with your finger to feel for any left over grit, then slap in the crank and put a prop on. Now you should be able to forcefully rotate the crank and feel for gravellyness, roughness, catches, etc. It should rotate and spin freely with no sudden stops or sluggish behavior. A flick of the prop should send it spinning freely for a few seconds.