Lean/seizure is the most common saw killer, and can be caused by a multitude of conditions.
On saws, one can adjust a brand new saw and seize it on good fresh fuel
mix, if the carb is adjustable. One can adjust the high speed screw in, and get @ 18,000 rpm for about 40 seconds, then the piston starts melting, and the rings get pinned down by molten piston metal.
Going leaner on the fuel air ratio, the saw will run a lot faster, bt since the
oil/lube is in the fuel supply, it also means less lubrication, and even making
things hotter, faster. Usually a piston damaged by a lean/seizure, the
main damage will be around the exhaust port, and some may be on the opposite side, but mainly the exhaust.
Now, a piston damaged by lack of oil in the mix, sometimes referred to
using the lean word, the damage will be all round the piston.
Lean seizure due to a lean air/fuel ratio can be caused by improper
adjustment, fuel line leaks, clogged fuel filter, clogged carb, air leaks
in the crankcase {seals, gaskets, etc.}, any thing that restricts the fuel,
or increases air to the engine.