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Cylinder scoring...Causes?

Discussion in 'Chainsaw' started by poulson01, Feb 9, 2008.

  1. poulson01

    poulson01 ArboristSite Operative

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    I have 3 saws with scored cylinders. 2 Husky 346xp(s') and an 024av. I blame my father in law for the Huskys. One is (was) his which has gone through two pistons and now the jug is killed. The other is mine, which I bought because I liked his. I lent it to him last month because his stopped running and now mine has low compression. I watched him running mine and he's bogging the saws down to the point that chain just stops and the saw is at full throttle. And he doesn't let up. A couple times I saw him running the saw just above the rpm that the clutch would start slipping. Made me sick!

    The 024, I don't know anything about. My step dad bought it for $25 and it had been sitting a while, judging by the fuel in it. The muffler screws were rattling around inside the muffler so I took it off to look. The piston is scratched up bad. I got it to run but it was bogging so I took the carb off. That side of the piston is just as bad.

    What are the causes and how can you prevent this? I can rattle off a few but I want to hear from the guys in the know.
     
  2. Urbicide

    Urbicide Addicted to ArboristSite

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    There are a number of reasons for this. You are over heating the saws and the metal is actually starting to melt. Can be as simple as lack of lubrication and/or crappy gas to forcing the saw to cut with a dull chain or an overly lean condition due to an improperly adjusted carburetor, bad crank seals, torn carburetor boot, cracked fuel line. Sounds like your step dad is a bit overly heavy handed too. What brand of 2 cycle mix and what mix ratio does he use? Is he using fresh premium gas preferably with the least amount of ethanol? (E 85 is a big no no). The original 346's were conceived as a high speed limbing saw. They need to be run at a high rpm without bogging them down. I assume that these 346's were the original 45 cc versions? You can replace the piston & cylinders with replacements for the new edition 346 (50cc). These new p & c's will not rev nearly as high as the originals but will have better torque. It is also very important to sharpen or change out the chain when it starts to get dull. You want chips and not saw dust. :chainsaw:
     
  3. Fish

    Fish Account Hold

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    Wen replacin pistons, one must find out wat caused te failure.
    sorry, my keyboard is still afflicted.
    I am trowin up some ood, new Stil manuals tommorrow on e-bay, put out by
    Stil, one is failure analysis, te oter on basic troublesootin.

    I would leave my wife for spillin tea on te keyboard, but se is a ottie.....
    ere is a pic of er testin out my bow last summer........
     
  4. poulson01

    poulson01 ArboristSite Operative

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    Crappy gas...Check.
    Dull chain...Check.

    He doesn't understand that, most of the time, if you take your time, you get done quicker. (I promise, that's the last time I ##### about it!)

    I'm more of a four stroke and diesel guy.
    If you run a two stroke at higher rpm, it runs cooler?
    If you bog it down, it'll overheat?
    His Husky is burned on the exhaust side. Clean on the intake side.
    The 024 is scratched up all around. Is that from the muffler being loose?
    The Husky muffler was falling off when I got it also. Is there a way to tell what caused what?
     
  5. Wood Cutter

    Wood Cutter ArboristSite Operative

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    Thats a easy one, loaning them out is what caused that. Otherwise bad gas, overheating, improper mix, improper carb adjustments, seal leak etc etc. Just my 2 cents.
     
  6. THALL10326

    THALL10326 The Champ

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    Urbicide summed it up pretty good far as why they score. As for that 024, if its scored up on both sides, intake and exhaust, that usually a sign of pure gas being run through the engine. The fuel coming into the intake side cools that side of the piston and rarely does it score unless the fuel has no oil in it.
    Most times only the exhaust side scores because it doesn't get the luxury of the intake side being cooled by the fuel mix.
     
  7. Fish

    Fish Account Hold

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  8. Crofter

    Crofter Addicted to ArboristSite

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    Fish, if she gets that double barrelled sling shot tangled up in the bow string I wont be looking to see if the arrow hit its mark!:clap:
     
  9. Gordie

    Gordie ArboristSite Operative

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    Fish,

    Trust me. She is sorry about the tea. :jawdrop: :jawdrop: :jawdrop:
     
  10. 58hydraglide

    58hydraglide ArboristSite Operative

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    Whoa!, Fish!,
    She could run straight gas through my least favorite saw and I wouldn't care!
    :) :) Just get her a sippy cup for when she's on the computer, give her a kiss and say " I luv you baby!"
     
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  11. motosierra

    motosierra AboristSite Guru

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    Damm!! Fish....no wonder you can't type !....oWeehhheeee!..are you kind of weeak in the knees hter buddy?.........nice picture!! I'm going back to look at her again!!

    See know I can't evnen tpype
     
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  12. Lakeside53

    Lakeside53 Stihl Wrenching

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    Too much plastic..
     
  13. maccall

    maccall AboristSite Guru

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    No problems, she'll last 1500 hours and then she'll just need a set of rings...
     
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  14. redprospector

    redprospector Addicted to ArboristSite

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    Might want to check to make sure the filter isn't dirty on the saw, and on Fish's girl.;)

    Andy
     
  15. Mad Professor

    Mad Professor Addicted to ArboristSite

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    I think somebody posted this here before:
     
  16. Log Splitter

    Log Splitter AboristSite Guru

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    Fish's picture was better.
     

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