© STIHL Inc., Virginia Beach, VA     2013 US/STR
confidential
16. Inspect Exhaust Port and Piston
 With the muffler removed use 
a flashlight and look through 
the exhaust port to be sure 
the port is not clogged up 
with carbon deposits
 Move the piston up and down 
and inspect the surface of the 
piston skirt for scoring or 
damage
 A piston in good condition 
will still have the radial 
machine marks across the 
skirt indicating little or no 
wear
© STIHL Inc., Virginia Beach, VA     2013 US/STR
confidential
16. Inspect Exhaust Port and Piston
 Spray some lubricant on 
the rings and when the 
flywheel is turned back 
and forth slightly it will be 
apparent if the rings are 
free in the lands
 Lower the piston to BDC
 Inspect the intake side of 
the cylinder wall for wear 
or damage