ORIGINAL: Scota4570
About half the saws I haveaquired have scored cylinders and pistons. The one a stripped downtoday could have made a decent engine, a Homelite 42cc. To bad it isruined. It is very low time, the top of the piston was hardly coveredby carbon. You could still read the laser marked parts numbers on thetop of the piston after cursory cleaning. The area around the exhaustport and less so the intake port were real badly galled. I triedsmoothing it up with 400 grit paper but even the ring is damaged. Thecompression is poor. It is almost like somebody put dirt in the sparkplug hole. The owner said his laborer told him it just stopped running.
So, is kind of thing usually from running gas without oil?
We are not worried about the piston/ring anymore. They are toast!
But look in the cylinder by the ports and examine the scratches. If there are deep gouges that you can feel with your finger nail the cylinder may be toast also?
But if your finger nail doesn't feel any roughness, a new piston and ring may save it