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coincidence ?? I think NOT!!! WARNING! 394 Carnage @ INSIDE!!!

Discussion in 'Chainsaw' started by SawGarage, Nov 17, 2010.

  1. SawGarage

    SawGarage Addicted to ArboristSite

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    So...

    got a LOW hr (yet, a bit beat up) 394 brought to me by a local guy yesterday...

    was a referral from another I've done a bunch of work for...he mentioned the 'top end on a buddy's 394 is locked up, could I help...." Course, I said yes I have a 394 I was in the process of rounding up parts for a build, and LUCKILY found a cyl for myself 3 months ago, so atleast I have one for this saw... my project will have to wait...

    BUT my saw will be cylinder-less :cry: so, on-goes the search again! :dizzy: Too bad it wasn't a 395! I'd love to try a BB!

    OK...on to the fun part!

    Piston crown...

    hmm...that's an odd mark...:

    [​IMG]




    Piston Side, and CHUNK outta the top edge BARF!


    [​IMG]


    now that's a REALLY ODD shaped mark....

    what in the WORLD could have made THIS mark??...


    [​IMG]


    Let's do some INVESTIGATING....



    hmmm..


    I did notice one thing that was DIFFERENT than most saws I've worked on (OR OWN!), when I picked up the pieces, LITERALLY (4 dealers would NOT touch it, and told the guy he should buy another ($1200) saw...:rolleyes: and another small engine guy wouldn't touch it...


    THIS is what I thought was different...

    HMMM...what an odd SHAPE...


    [​IMG]



    Now it's like a PUZZLE!

    looks like it might FIT!

    [​IMG]



    NOT sure about those E3 plugs!!! WTF!!!! I HOPE the owner did NOT try and gap the plug (Your not supposed to..but I DOUBT he would have...)



    The side electrode almost looks BRAZED on!!! and it's thinner than a standard Bosch/NGK/Champion, etc...
     
    AT sawyer and lesorubcheek like this.
  2. SawGarage

    SawGarage Addicted to ArboristSite

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    hmm....seems to fit good... :angry:


    [​IMG]

    [​IMG]



    sad thing is, I don't think HOME DEPOT even sells REGULAR OLD TRIED AND TRUE plugs anymore...


    I gotta talk with the owner, and get more info... he was blaming himself for dropping some crud into the cyl... hmmm..


    Jay
     
    Last edited: Nov 17, 2010
  3. Steveo_supremo

    Steveo_supremo AboristSite Guru

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    Dang, and I was going to put those plugs in all my saws because I heard they increase the power output by 20 thousandths of a percent and reduce fuel consumption by 1/3 of a drop per tankful.
     
  4. SawGarage

    SawGarage Addicted to ArboristSite

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    They come in a green package too :rolleyes:
     
  5. 7sleeper

    7sleeper Addicted to ArboristSite

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    Very nice info!

    7
     
  6. SkippyKtm

    SkippyKtm The Lorax, my FIL rip...

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    Look like gimmicky ol' junk plugs, I'll stick with Bosch...:dizzy:
     
  7. TFPace

    TFPace ArboristSite Operative

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    Great troubleshooting skills! Thanks!!!
     
  8. Rookie1

    Rookie1 Addicted to ArboristSite

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    So You think the elctrode broke off E3 plug. Is the plug you have a replacement? Im confused.:confused:
     
  9. woodshave

    woodshave ArboristSite Lurker

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    Yeah, I'm confused too. How did the electrode get down to the piston?

    ...And maybe someone can explain those multiple point electrode plugs to me. Electricity will only arc across the path of LEAST resistance. There can't be two paths of least resistance. So, the spark is only going to be at one point at any given time. These ads you see with sparks in 2 or more places is complete crap. As soon as there is a little oil film on the plug the spark will only happen at one spot consistently.
     
    chopperfreak2k1 likes this.
  10. JayB

    JayB ArboristSite Member

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    This IS the perfect explanation of those plugs! (Facts not to be confused with the sales pitch)
     
  11. SawGarage

    SawGarage Addicted to ArboristSite

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    YES, I'm assuming a replacement... It would have to be...not like the plug side-electrode is going to reattach itself after it leaves the port! lol :jester:


    I agree...sometimes the spark will jump from side to side. I think the idea here is the open-ness of the center electrode, so the spark is 'viewed' better by the whole combustion chamber...but one the explosion happens, it really doesn't matter much...

    Kinda like what Stevo- said...maybe a 1/10 oz per tank full...we SPILL more out of our saws!


    J
     
  12. sjp

    sjp ArboristSite Operative

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    i tryed them a year ago
    the electrode strap broke and was rattling in cylinder
     
  13. Chris J.

    Chris J. Addicted to ArboristSite

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    Good sir, you are the Sherlock Holmes of chainsaw mechtechs.
    .
     
  14. SawGarage

    SawGarage Addicted to ArboristSite

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    exactly...

    'cept in this case, with the saw @ 10k RPM, and with hearing protection....

    well, it finally got wedged in between the cyl and piston... :eek:



    :clap: :Eye::Eye:
     
  15. Taxmantoo

    Taxmantoo Plays with chainsaws

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    Product liability?
    "Your plug destroyed a $1200 engine. Pay up."
     
  16. hanniedog

    hanniedog Addicted to ArboristSite

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    Is that made by the ACME company where the coyote got all his wiz bang products.
     
  17. SawGarage

    SawGarage Addicted to ArboristSite

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    yeah...no kidding... I think I'll be giving them a call...

    they'll probably want the saw for 'analysis'... or some level of BS :bang: :chainsawguy:


    LOL.... poof.
     
  18. Grande Dog

    Grande Dog ArboristSite.com Sponsor

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    Howdy,
    When I first saw those pictures I thought spark plug. I was thinking it was the curved grounding electrode because of the picture with the perspective view. I would think that if it was the type of electrode shown, the impression would be more of a right angle "V" shape.
    The other thing is that if it was the style of electrode shown that was the cause, the whole electrode would have been intact to keep the ears in position.
    If it was that strange electrode, you would think that the top of the port and the cylinder would have been hammered real bad. Any photos of the cylinder?
    Regards
    Gregg
     
  19. SawGarage

    SawGarage Addicted to ArboristSite

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    Gregg, my friend... Gregg, Gregg, Gregg..

    Surely your not second guessing the GREAT Sherlock Holmes???? :laugh: :poke:

    ---look at HOW WIDE the mark is on the side of the piston... same width as this WIDE electrode ...and it's perfectly symmetrical...:confused:

    ---when a electrode bounces in a cyl @ xxxx ft per sec, what is to determine WHICH orientation it would have when being blown out the exhaust?? :confused:

    ---Yes the top of the port WAS hammered....

    I took a cell pic (didn't have the camera in the shop....I brought the slug in the house., let's see how it looks....


    [​IMG]


    The HARDEST hit was at about a 45 deg on the piston......Right in line with the factory port chamfer.




    Gregg, do you sell these plugs??
     
  20. willysmn

    willysmn ArboristSite Operative

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    394 carnage

    Very nice photos and thinking. Sorry it takes your newly found
    cylinder, though.
    However, I think the ground electrode must have wedged pretty quickly or there would be more marks on the piston top.
    Of course at 10k rpm pretty quickly is who knows.
     

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