Chainsaw Repair

What model Stihl? Actually Roger, I believe the Partner/HVA saws have a poor filtration system design compared to Stihl. Almost every one I see has some sort of C/P scoring. The other thing is that the users NEVER seem to use the built in water spray when cutting, perhaps the use of the water which is designed to keep the dust down would contribute to the longevity of the saw by sort of helping the filter system out? Rarely do I see a Stihl with scoring unless it is raw gas related.

The Stihls were 2 TS 400 one TS 420 and a TS 510.   The 510 was a big heavy saw with a 12" diamond blade on it.   When I revved that thing up it was like hanging onto a large gyroscope.
 The scoring I found in the Huskys was severe and had to be caused by a lean condition or straight gas.    I did find a Husqvarna 970 I believe it was, where cement dust had worked into the throttle shaft of the carb and it started to wallow out causing an air leak.
  I agree with you on the water.   These things have so much cement dust in them it is a wonder they still worked at all.