Chainsaw Repair

Perhaps there is another way to figure out what may have happened before pulling the muffler. If as 660 and I both suspect the saw was raw gassed. If there is still fuel in the tank you could pour a small amount in a kitty food can and let it evaporate. If there is no mix oil left in the can after the gas evaporates off then chances are that the saw was fed improper fuel. If there is oil left in the can then we pull the muffler to have a look, because it is possible that the wrong amount of oil was added to the gas. If after pulling the muffler the piston does not look as 660 described then we need to look further.

Before attempting any sort of repair you must first figure out just what caused the saw to fail. It is after all, a 1998 16 year old saw. There are lots of other things that can cause the sort of situation you are dealing with; failed bearing, seals, air leaks in the intake tract etc. The repair must not only cure the resultant damage, it must also address the cause. Otherwise it will happen again.