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Stihl BR 600 winter mode question

Discussion in 'Mechanic and Repair' started by cakey, Oct 2, 2013.

  1. cakey

    cakey LawnSite Member
    Messages: 14

    I'm a new mechanic, kind of fell into it so I'm still quit ignorant that being said i maintain about 16 Stihl BR 600's we use them summer and winter. I was putting them in winter mode earlier but I don't completely understand what this accomplishes. More accurately it seems counter intuitive to me. It seems like winter mode allows more air into the machine and summer mode allows less air in. I would think you would want the opposite, although my observation could be wrong. Could anyone explain to me what the winter / summer mode accomplishes? Thank you.
  2. cakey

    cakey LawnSite Member
    Messages: 14

    I think i figured it out, its pulling warm air in that runs by the engine first instead of cold air from the other side.
  3. rlitman

    rlitman LawnSite Bronze Member
    Messages: 1,732

    Yep. It's there to keep the carb from icing up.
  4. cakey

    cakey LawnSite Member
    Messages: 14

    Thanks, ya i took another look at it and it made more sense. We run these things down to 40 bellow so it seems to be effective.
  5. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Messages: 759

    That would be correct...

    Winter mode (with the deflector open) allows warn air from the engine to enter the carburetor to help prevent "icing".

    Summer mode (with deflector closed) allows no direct warm air from the engine to enter the carburetor.

    Keep in mind that "icing" can happen with ambiant tempetures above 32 degrees also!

    Also make sure to switch from winter mode back to summer mode in spring so the engine will not overheat!

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