Chain saw throwing chain

Discussion in 'Mechanic and Repair' started by fireman649, Jul 19, 2006.

  1. fireman649

    fireman649 LawnSite Member
    Posts: 76

    I have a Echo CS 346 Chainsaw that keeps throwing the chain off. I've replaced the bar, chain, and all adjusting mechanisms. It's still throwing the chain when cutting hard. I'm going to get a new sprocket to try. What do you think?

    Thanks,

    Steve
     
  2. Audrey

    Audrey LawnSite Senior Member
    from Pa.
    Posts: 570

    When cutting hard?
    Are you keeping the bar straight? Not canting it when getting into the cut I mean. If you have the chain tension a bit too loose and if you were to c0ck the bar....
    You DO have the correct chain for the saw/bar?


    A
     
  3. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Posts: 472

    What size bar? IMHO, the longer the bar, the more critical the tension adjustment, alignment and all other considerations.
    I trust the saw is oiling properly?
    I trust your bar has a tip roller which you are keeping greased properly? I use Permatex anti seize grease applied with a needle point nipple.
     
  4. fly-4-fun

    fly-4-fun LawnSite Member
    Posts: 0

    If the saw has some hours on it, then the clutch sprocket might be your problem. I'd replace it and try again......:usflag:
     
  5. fireman649

    fireman649 LawnSite Member
    Posts: 76

    The chain tension is correct, and no it is not being cocked while cutting. It is abrand new chain(yes, the right one) and a new bar(so the end is fine). I'm going to replace the sprocket and see what happens. I'll let you know. Thanks for the replies so far.
     
  6. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Posts: 472

    I trust the saw _does_ actually cut when you ease it into wood.
    My friend had me look at his saw once and, this is a really butt suck thing to say, but the chain ain't on backwards is it?
     
  7. AAELI

    AAELI LawnSite Senior Member
    Posts: 362

    Make sure your drive sprocket is not worn and on the subject of chain, verify that not just the length is correct but also pitch. Having a new chain and bar makes no difference if the pitch of the chain is incorrect. Double check.
     
  8. themowerman

    themowerman LawnSite Senior Member
    from NJ
    Posts: 297

    Most of the time when a chain keeps coming off is due to one or more of the drive links in the chain having a burr on them. If your chain is thrown due to it being loose the drive sprocket usually burrs up the drive links. Make sure that every drive link fits into the bar groove freely. If you find one with a burr just file it so it fits again.
     
  9. AAELI

    AAELI LawnSite Senior Member
    Posts: 362


    Hey Mowerman, You are right. Not tensioning the chain properly after it stretches causes the problem you mention.

    Only he just said that all the above was new.. If it throws the new chain I would suspect the wrong pitch on chain or drive sprocket or even bar pitch. I get them in the shop like that often. People buy their bar/chains at Ace Hardware or Kmart without getting the right one and bring it to me as we are just about the only shop on island that puts chains together for all brands, pitch and guage combos.
     
  10. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Posts: 472

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