Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Echo => Topic started by: Giles on February 02, 2013, 04:37:37 pm

Title: Echo CS400 Piston Fit?
Post by: Giles on February 02, 2013, 04:37:37 pm
I have rebuilt chainsaws and other small engines for over 50 years. I recently purchased a CS400 that is absolutly like new. It even had a small amount of styrofoam packing remaining. Regardless--someone evidently straight gassed it and I have it torn down. Every engine must have a certain amount of clearance between the piston and cylinder, but this Echo has very little. App. .002 total.
 This seems too tight to me--like the piston will slowly fall into the cylinder from garavty. Upon inspection, the piston was slightly scored in one particular spot and cleaned up very good. The cylinder has a small area, about half the size of a pencil eraser after a LIGHT HONEING. This spot is below piston ring travel so I fell that both parts are useable.
 Through some research, I have learned that Echo may have had some problems with P/C scoring from, supposably, too tight a fit.
 I know that Echo coats the piston and cylinder so I do not want to remove this with additional honing.
 Any suggestions?
Title: Re: Echo CS400 Piston Fit?
Post by: Cut4fun . on February 02, 2013, 05:41:04 pm
  Scoring is from straight gassing it?  Maybe out of round cylinder or piston slipped by. All just WAGS.