My Stihl 034 super is locked up. However, when I remove the plug the saw will pull easily. I checked the intake and the exhaust and neither are plugged. Do I need to pull the head and check the rings?

Garry Steiner, August 2009

Check to see if your spark plug is right one. If it is too long it will stop the piston. I use an Autolite 255 plug in all my saws, trimmers and such with out problems. You can use the Autolite 255 or competitor equivilant. It is going to be stubby plug.

David Trowbridge, October 2009