It sounds like you might have a couple of injectors that are dribbling after shut down. You end up with a puddle of liquid fuel sitting on top of the piston when you attempt to restart. If the prechambers need reaming you'll know when you pull the glow plugs, they'll come right out of a clean chamber but you need to worry them out of a coked up hole. See if you can find a local shop to pop test your injectors for a reasonable price if you pull them and carry them in.

Bob D.