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Air filter issue with Eager Beaver 35cc chainsaw ?

Post in 'The Gear' started by KeithO, Sep 29, 2007.

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  1. KeithO

    KeithO Minister of Fire

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    Hi

    Since I have not been through a winter with my wood stove yet in Michigan, and since I have been funding everything (stove, chimney, chainsaw, splitting axes etc) this year, I decided to get a relatively lightweight chainsaw "for starters".

    Now I have to say that off the bat, this chainsaw works out pretty good for me and I like its light weight. By the time I run out of gas I generally need a break (and typically have to swat a few thousand mosquitos that have been feeding off me while I have been busy.

    One of the problems I have found though, it that apparently the air filter is hopelessly undersized on this unit. It is a single (flat) layer membrane type filter. It is not pleated in any way, which would increase the surface area for contaminants. After a few days use from new, I found that the unit lost a lot of power and was "four stroking" all of the time and wouldn't idle. So in looking for the problem, I came upon the air filter. The pictures below show what it looks like: http://www.flickr.com/photos/11828061@N04/sets/72157602200288785/

    Basically, the surface area of the filter element is so small and restrictive, that the sawdust that is able to reach the filter while cutting through an 8" round is sufficient to create a noticible loss of performance. Once the filter has been clogged a few times, it appears that all attempts to clean it are only partially effective and performance drops off after just a few minutes of use.

    Has anyone experienced this problem ? Are there any replacement filter with larger pleated elements ? Perhaps replacing the entire airbox ?

    Other than this issue I think the saw works just fine, but this appears to be a major design flaw.

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  2. KeithO

    KeithO Minister of Fire

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    No Takers ? How about someone else with a "quality" chain saw posting a pic of their airfilter for comparison ?
  3. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    It is as big as the ones on my Husky 142's and the Poulan 2450. I have never seen pleated filters on any chainsaw and all of them need cleaning after a cutting session. And I have never taken the air filter off of a chainsaw that didn't have sawdust in the carb throat.

    It's a dirty job those suckers have to do.
  4. KeithO

    KeithO Minister of Fire

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    Well, I had to do something, so I took out the filter element and scrubbed it with soap and water and tried to reverse flush anything I could out of it.

    The difference was like day and night. I cut down a standing oak tree about 18" in diameter and that baby just screamed all the way. A cut through all the way in about a minute. Its the first time I cut down a live tree, everything else till now has been standing dead wood and dry as a bone, so the rate that the little saw plowed through took me by surprise.

    I guess that if one cuts only dead standing wood the sawdust is more than likely finer and tends to clog the filter more severely than if one cuts green wood.

    At least now I know... Perhaps I will buy a few replacement filters so that if it bogs down in the future when I'm out in the woods I have something to swap out right away.
    Keith
  5. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Another thing is that standing dead trees that have been there a long time are like trying to cut a brick. Chains skate on the wood more than dig in. With live or recently dead trees they bite right in. Dead trees dull the heck out of chains and for some reason there is always a lot of dirt (read: sand) in the bottom few feet of them that is really abrasive.
  6. Gooserider

    Gooserider Mod Emeritus

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    The filter on my Poulan cheapo saw is about the same size, but it's a hunk of green sponge that pushes into the airbox. And yes, there is sawdust in the carb throat.

    While I'm sure that cleaning the filter helped, it is worth noting that live green wood cuts much easier than dry dead stuff.

    Gooserider
  7. KeithO

    KeithO Minister of Fire

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    Gooserider (not sure you like being called Goose ?)

    The motor ran at double the RPM after cleaning, which it wouldn't do before even if unloaded !

    Sponge would be a lot better than the flat paper element since it offers much more space for debris to go (storage capacity). I know how filters are designed and I'm amazed to find such a crappy filter on a tool that is obviously not going to be working in a clean environment.

    I think that in my case the sawdust falls in during removal of the tight fitting element, I don't think it is a bypass.
  8. Gooserider

    Gooserider Mod Emeritus

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    Don't worry about it - everybody else calls me Goose... I answer to either :coolsmile:

    I'm not doubting that cleaning the element helped - don't get me wrong on that. I was just pointing out that all else being equal (i.e. kind of wood, etc) green wood generally cuts easier, and tends to produce larger chips as opposed to sawdust. (I suspect because the chips made when cutting dry wood tend to crumble more as they get pushed through the cut) Mostly my intent in saying that was to say that the element cleaning was probably not the ONLY factor in improving the performance.

    Is there any way to swap in a sponge or other better quality filter (assuming warranty presevation isn't an issue?) I know that on many motorcycles it isn't unusual to replace over priced and/or restrictive filters with aftermarket or home-brew replacement filters - many made by cutting out the factory paper element and replacing it with various sorts of foam. The filter in your picture looked like it would fit into some sort of frame - could you get a larger foam filter and cut something the appropriate shape to fit?

    I fell that on my saw it is more likely a bypass - I was watching pretty closely when pulling the filter, and usually tilt the saw when pulling the filter so that any debris would fall away from the carb. All the stuff in the carb throat is fine dust size, much smaller than most of what was on the filter. Lastly the debris was pretty evenly distributed over the surfaces under the filter - if it was fall-in, I would have expected it to be in clumps, but this looked like an airflow distribution...

    However so far it hasn't seemed to hurt the way the saw runs, so I'm not worrying about it terribly.

    Gooserider

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