Stihl 026 - scored cylinder

[rubantin]

I put in a new piston, ring, cylinder and carb kit this summer... ran it about 10 hours and it started acting funny and not idling. So, I decided to replace seals today. The new cylinder is scored just below the exhaust port... Piston is scored in the same place...

Any ideas?

 

[stihl for life]

Lean or something got in there and scored it

 

[lone wolf]

I put in a new piston, ring, cylinder and carb kit this summer... ran it about 10 hours and it started acting funny and not idling. So, I decided to replace seals today. The new cylinder is scored just below the exhaust port... Piston is scored in the same place...

Any ideas?

Is the ring stuck? If so try to free it up. Pics would help.
What brand parts were used?
You should vac-pressure test at this point .

 

[AKDoug]

Why did you put a new cylinder on in the first place? If you didn't fix the reason why it scored in the first place, a rebuild without vac/press testing is likely to result in the same issue all over again.

 

[CR888]

+1 on advice above sounds like the original problem (poss air leak) has not been fixed. You NEED to find that problem.