Most never did have problems and have been running fine all along. My first year, (first shipment in fact), 555 did have a severe case of the hot start problem, but on those earliest saws, the coil was the main culprit. Changed it out and no problems ever since. Some of the early problems had more than one cause. The 555's didn't run any cooler than the 562's did. Haven't run my 555 in ages; have to drag that out this Fall. The 2016 case update on the 562 was also done on the 555. Should not have added any weight though, unless changing the clutch side from magnesium to aluminum adds an ounce or a couple of grams. The improvement was primarily in the bearings, both in durability as well as better fit to the crank and case. At the same time this is when the clutch was changed; might add a couple more grams there. (Needs a different clutch tool.) They also started adding "dry lock" to the oil pump screws for improved sealing as like on most saws the oil pump screws go through the case. So, the new 555's aren't different in power or weight from what you and I have. But they are significantly improved. Problem is that they are priced only $50 less than the 562, so nobody buys them. Plus they now have the 550M2 nipping at it's heals. It's a shame, cause it's a great saw. The pricing thing applies to the 545M2 and 565 too. But ya gotta look at it from the "glass is half full" perspective of aggressive pricing on the XP models, not as though saws like the 555 are over priced.