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Stihl Backpack & Catalytic Converter

Discussion in 'Lawn Mowing' started by DFW Area Landscaper, Oct 8, 2003.

  1. DFW Area Landscaper

    DFW Area Landscaper LawnSite Silver Member
    from DFW, TX
    Messages: 2,116

    On the Stihl backpack blower, they install a catalytic converter on the exhaust port. When this thing starts to get clogged, there is a HUGE loss of power. The way to fix it is to take it off with a pair of pliers, hold it to a blow torch and burn all the carbon deposits off.

    But what happens if you simply remove the catalytic converter and never put it back on? I've removed mine in the field for a day or so and everything runs fine. Outside of the EPA, is there any reason at all to have that thing on there? Will removing it damage the equipment some how?

    DFW Area Landscaper
  2. mike9497

    mike9497 LawnSite Senior Member
    Messages: 954

    i know shin also has cats on there blowers.they have to sell them with the cat systems because of the EPA standards,but that doesn't mean you need to leave it on. i know ever since i bought my mustang back in 98 the first thing to come off that car was the cats.now does it run better? yes.will it pass emissions?? it will pass the first 3 tests but it fails the 4th which is called knocks.cats help burn up raw fuel that didn't burn in the cyclinder
  3. mtdman

    mtdman LawnSite Gold Member
    Messages: 3,143

    Are you talking about that screen over the exhaust port? The one that gets clogged up and then the machine won't run? If so, I have removed all of mine. My very 1st stihl wacker got clogged like that about a month after I bought it. When I finally figured out what it was, my dealer told me just to leave it off. I guess you can waste time burning off the carbon every month, I dunno. I just don't use them on mine. Wackers or blowers.
  4. Tx Firefighter

    Tx Firefighter LawnSite Member
    Messages: 76

    My dealer pulled my screens out when I bought the equipment. He told me they are spark arrestors for usage on Federal properties which require them to be used. He said since I don't mow any Federal props, he'd remove them now so I don't come back in a month with a bad running problem.

    It's a stupid government law deal.:rolleyes:
  5. grass_cuttin_fool

    grass_cuttin_fool LawnSite Gold Member
    Messages: 3,526

    yep i just bought a stihl last week and the dealer said to take it off and clean it with a torch or just put it in the trash, think im gonna keep mine on and see how it goes since mine is gonna be workin in dry leaves soon, he he i have enuff bad luck with out any more
  6. proenterprises

    proenterprises LawnSite Silver Member
    Messages: 2,296

    thanks for bringing this up...i was starting to think that their was gonna be no hope for my 420c magnum. it dosent have many hours on it but i think i will rip it off to aviod problems.

    if someone dosent mind...could you explain how to take them off the correct way so this dumbass dosent mess somthing up:dizzy:

    thanks guys!
  7. Meier

    Meier LawnSite Senior Member
    from DFW
    Messages: 269

    I just use a pair of needle nose pliers. It's pretty simple once you look at it.

    Has anyone been running their equipment for a long period of time, like over a year, and experienced no problems after removing that screen?

    DFW Area Landscaper
  8. Lowcountry Lawn Care

    Lowcountry Lawn Care LawnSite Member
    Messages: 51

    I've been running my stihl without it for over a year without it and i haven't had a single problem (knock on wood).
  9. mtdman

    mtdman LawnSite Gold Member
    Messages: 3,143

    Like I said, I remove all screens from all the 2cycle stihl products. I've run my wackers and blowers for years, NEVER had a problem with running without the screen. Just take a pair of needle nose pliers, squeeze that clamp, take off the screen and the clamp. Takes 2 minutes.

    Also, for the 420 I'm going to give you a tip. Stihl made the new blowers with a bigger tube. When I got my 420 last spring, I hated it because I thought it had no power. I got the attachment for the bigger tube that narrows down to the old size tube, so you can also put the curved end piece on as well. MAJOR DIFFERENCE in power output. The adapter is like $12 and another $12 for the j tube. I highly recommend it.

  10. Richard Martin

    Richard Martin LawnSite Fanatic
    Messages: 14,699

    The Stihl BR420 C (C stands for catalitic) does have a catalitic convertor. It does weigh more and it does rob power. The convertor is built into the muffler. The regular muffler from a non C model bolts right up and restores power to the blower.

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