Would go with maybe Lightning's bearing diagnosis though would definitely look at the starter spool/rope. This has been an issue on a 361, 251, and 250 for me I've recently rebuilt to various degrees, which were maintained poorly and abused badly by others. Assumed hydrolock, but doubtful. Has been as bad after taking plug out and clearing cylinder and putting plug back in. Everything else the same as you describe. The fix for me - at least for now - has been putting a drill and socket on the flywheel nut and turning the engine for a good while. In one case it was also a bad starter cord spool binding up. Most all three saws were impossible to pull til I spun them a bunch with the drill. Then they pulled fine. Many folks go to sheared flywheel keys, timing kickback, or hydrolock, when I think this kind of thing on these Stihls is more often as suggested, bad starter cords/spools or bearings binding up. My experience leans toward bearings, some lubrication from sustained turning the engine over freed the saw up in nearly every case (the 361 is still a bit problematic - may be the starter spool is the remaining sticky point on it).