Small Engines (Lawn Mowers, etc.): compression, head gasket, minimum compression

Question
I have a 42 cc 18inch craftsman chain saw that will not start. There is spark but the compression only gets to 60psi gas is getting in the carb and I even tryed to use quick start just to turn it over but nothing at all... what is my likly problems
thanks

Answer
Air compression seems to be very low I would think minimum compression is at least 90 pounds per square inch.  The only other things would be a plugged spark arrestor in your muffler or crankcase seals.  If the head is removable it could be a head gasket as well when I say had I mean cylinder.  If you're going to pull the cylinder off check your rings to see if they are worn on one side of this is normal.  Put them in the cylinder and check your ring and the gap.  If it is excessive you'll have to replace the cylinder and rings.  Good luck on your project I hope this information helps.