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Chainsaw bogs down at high speed

Discussion in 'Chainsaw' started by reaperman, Dec 28, 2007.

  1. reaperman

    reaperman AboristSite Guru

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    My stihl 044, saw is starting to bog down at full throttle. Its more pronounced when the saw is first started cold. After starting the saw I rev it up and down to warm it up. But when it hits wide open it bogs, so I feather the throttle to keep it going. When I start to cut it warms up and runs better. But as soon as it is rev'd wide open it loosed some power. If I back it off to 3/4 throttle, it rev's higher. I can feather it to wide open, but if I "crack it" and hold it wide open it can't catch up and I'll have to let it idle down and feather it to wide open. The saw runs great at a idle, and I can still cut, but full power is just not there. :dizzy: I always use high octane gas with stihl oil. Maybe the high setting on the carb needs to be adjusted, I havent tried that because it has always run great since I had the saw (13 years). I didnt want to start messing with the carb adjustments until I came before the experts (thats you guys), first.

    One other note, I put a new piston in the saw about 4-5 years ago, the old piston for some reason just shattered. I dont think this has anything to do with the current problem. I've cut a lot of wood since replacing the piston.
     
  2. windthrown

    windthrown Addicted to ArboristSite

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    Sounds like you are running out of torque! (ha ha)

    You probably need to adjust the H setting screw on the carb. Turn it all the way in to seat it and then turn it out the number of turns marked on the side (if there are marks left, usually 3/4 or 1 full turn). If it it is not that it probably is a clog in the carb someplace or in the fuel line.

    My best guess anyway. You should be re-tuning the carb about once a year (at least) to get the best running idle, L and H settings. They tend to move around some over time and use. Also check that the carb is fully seated/bolted onto the manafold; sometimes you can get air leaks over if the gasket dries out or the nuts come loose (again over time and use).
     
    Last edited: Dec 29, 2007
  3. ericjeeper

    ericjeeper Addicted to ArboristSite

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    Get her warmed up

    Put it in a log running wide open and hit the kill switch.. Then pull the sparkplug., Compare it to a 3 year old carhart coat. If white richen it up a lot.. if black lean it out.
     
  4. chainsaw kid

    chainsaw kid ArboristSite Operative

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    suck squeeze bang blow

    Did this problem come on all at once or did it gradually get to where it's at now?
     
  5. reaperman

    reaperman AboristSite Guru

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    I never noticed this last year. And I'm first starting to cut again now. So the saw has pretty much sat since last winter when I did the majority of my cutting. I'll try the carb adjustment mentioned in the first reply, I never knew what that 4/3 meant before. And I'm not to familiar with carbs to go screwing in the settings. I remember I couldnt believe how small the carb actually is when I took it out to replace that piston. Thanks for replies.
     
  6. chainsaw kid

    chainsaw kid ArboristSite Operative

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    So it sat for a wile.....Whens the last time you rebuilt the carb? You can and should try the carb adjustment but a fresh carb is nice.
     
  7. Lakeside53

    Lakeside53 Stihl Wrenching

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    Sounds like you have an air leak... get or do a pressure and vac test.
    I assume you've been changing your fuel filter now and then?
     
  8. mountainlake

    mountainlake Addicted to ArboristSite

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    Sitting for almost a year I'd clean the carb first and check lines for cracks. Don't use gas with ethonal and put Stabil or something like that for storing. Gas seems to get worse every year. Steve
     
  9. chainsaw kid

    chainsaw kid ArboristSite Operative

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    Andy, I thought a sign of an air leak would be the saw idleing weird or it taking off on it's own. I know you are a welth of knowledge, please explain...
    I could see the filter as being a problem though.

    Reaperman, How is the compression? Why did a piston shatter a few years back? How dose your muffler look...is it clean?
     
  10. West Texas

    West Texas AboristSite Guru

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    I just fixed an 026 with the same problem, started, ran, idled but would cough and die in the cut. After doing a compression, piston, cylinder, plug, and seal test, I pulled the carb and put in a new repair kit. Still a problem. Found junk in the gas tank;but,filter was OK. After screwing with that carb for far longer than it was worth, I put in a used carb that I had in the shop as a backup. Problem solved. My belief is there is some junk in that carb that normal cleaning, disassembly, blowing with air gun, replacement of parts, etc, did not solve.

    Now I'll take it apart one more time and soak it in carb cleaner overnight; put it back together and try it on one of my 026's and see if that has solved the problem. If not, toss it. My time, even as a retiree, eventually becomes more valuable than an old carb. :cheers:
     
    Last edited: Dec 29, 2007
  11. reaperman

    reaperman AboristSite Guru

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    Update:

    Windthrown was correct

    I turned the high idle screw all the way in and backed it off one full turn and its running great.

    Another question: The plug is on the white-side, so I'd like to richen it up a bit. The bottom adjustment has the letters LA which way do I turn that bottom screw to make it run a bit richer??
     
  12. windthrown

    windthrown Addicted to ArboristSite

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    Well, I just love being RIGHT sometimes...

    The LA screw is the idle set screw. Use that to adjust the idle speed. I set my idle to just where the chain stops running (clutch does not engage). That does not effect the mix though.

    To get a more rich mix turn the H screw OUT a tad more. Maybe 1/8 to 1/4 turn. Maybe richen up the L screw OUT a tad as well. That is a little harder to get right. I set the L screw for best idle and throttle response. More of a 'set by feel' than anything else. Usually a 0 to 1/4 turn more than the factory setting.

    If you want to err... err on the rich side. A lean mix can blow your engine in a hurry. Which has me wondering why they have limiter caps that can only be adjusted toward running lean... :monkey: :)censored: EPA)
     
    Last edited: Dec 29, 2007
    Ole Farmerbuck likes this.
  13. reaperman

    reaperman AboristSite Guru

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    Since it is running good now, maybe I'll cut for an afternoon and check the plug again. I only ran it for a couple of minutes after setting the idle screw.
    It was turned out about 1 1/2 turns before taking the correct advice on how to set it. I just dont want it running too lean, and risk blowing another piston again.

    I'm not sure why the piston shattered on me a few years back. I was just limbing out a tree and the saw just quit. I tried to pull the rip-cord, and "no dice". The local stihl dealer ordered me a piston ($125). I had him look at the cylinder wall first and get his opinion, he said it looked good. But couldnt really give me a reason as why it happened. I put the piston in myself and took it back to him to fine tune it ($2, couldn't beat that). And it ran great ever since.

    I wish I could buy gas without ethnol, but Minnesota state law says 10% in every gallon. I normally dont use stabil, because when I mix up a gallon, its usually gone with in a week or so. Maybe I should start using seafoam or something anyway,for a cheap insurance policy. Thanks for the replies guys, its a helpless feeling when my baby's (044) sick. It very rarely happens but when it does its desperate times.
     
  14. windthrown

    windthrown Addicted to ArboristSite

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    Yah, the corn lobby at work = 10% ethanol in gas. We are fortunate to have real gas available here, though a lot of it around here is 90/10, which is all they can get in the bigger cities. Never mind CA gas... ethanol is bad enough on seals and gaskets, MTBE was terrible, at first more or less mandated by CA air quality, then banned. They have mainly ethanol mix there now, but some stations out of the cities have all gas.
     
  15. RiverRat2

    RiverRat2 Serio Tree Freak

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    save this link to your favorites,, ITs a good one for adjusting carbs!!!!

    http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

    Get some Stihl Ultra Pre mix its synthetic and it keeps your motor internals clean and extremely well lubricated,,,, It also has a stabilizer in it already,,,,

    As for the crummy gas you could go to one of the local general aviation airports and get a couple of gallons of some 105 octane av-gas,,,, there wont be any alcohol in it,,,,,,

    River,,,
     
    Last edited: Dec 30, 2007
  16. chainsaw kid

    chainsaw kid ArboristSite Operative

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    Rebuild the carb

    That's awesome you got it running good again by adjusting the carb! That's what I'd do first off. In my way of thinking, you did some troubleshooting. In the 13 years you'v had that saw, when is the last time you rebuilt the carb? If you haven't rebuilt it, use the saw a little and you'll see you probably like it. Then, buy a $10.00 carb rebuild kit and rebuild the carb, adj it again and I bet it will be outstanding and you'll love it :)

    Reason being is that parts inside the carb that come in that kit, are normal wear items that over time shrink/wear out therefore not optimizing your saws performance. Yes the h & s needles can/do move a tad with nml usage, but if you have to make drastic changes in a year....rebuild the carb and you won't have to worry about that potential problem.

    Note: this is my logic and if I am wrong, someone please post saying so.
    I'm always willing to learn.

    Kevin
     
  17. mountainlake

    mountainlake Addicted to ArboristSite

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    I like your way of thinking, start with the simple stuff. Most likely when he turned the high adjuster all the way in it dislodged some crud and cleared it out. That adjuster didn't move from the time he stored it when it was running good to when he started it again. One turn out is a starting point for adjustment not the final setting, I turn the the low out a little more after carb work as it will start a lot faster. Steve
     
  18. logbutcher

    logbutcher Banned

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  19. reaperman

    reaperman AboristSite Guru

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    I have never re-built the carb, nor have I really done any repairs since the beginning. It always seemed to run fine. I bought the saw used (less than 2 hrs) from a friend who thought he was going to cut wood for cash. But he found out cutting wood is work, and he is lazy. I had just purchased my propery (1993), 45 wooded acres, and he offered me the saw for $500. I had a olympic saw at the time and sold it to another friend. So I guess I've pretty much had it from the start.

    I would be interested in re-building the carb, I have a stihl dealer within 2 miles of my place. Is that the best place to get the kit or online? One thing I did notice before I adjusted the carb, the saw took a few more pulls (maybe 10) to get it started form cold. After, 3-4. Would I need the serial number off the saw to get the correct carb kit or is there a # on the carb itself. I looked for the serial # and I think I found it next to the muffler, above the chain on the body of the saw, 125155675 . Does this look right? Also, would you recommend taking the saw to the dealer after I'm done cutting for the season for a general tune-up? Or maybe have it done now? I do have another saw a husky 137, a little #### I got free when I bought my woodsplitter. It actually cuts pretty well for a small saw, I have been cutting smaller stuff with that and the bigger logs with the 044. So I could just use the husky until mine was done with a tune-up if I had to.
     
  20. Lakeside53

    Lakeside53 Stihl Wrenching

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    125? that's one of the early 044's...

    Best to take the carb type (ZAMA or WALBRO), and type. If your dealer sells you a Stihl kit, it's more expensive, but he may also sell aftermarket (many do). A full C3M Zama kit online is $5-7, plus shipping. Locally (around here they sell for $10-15).


    Annual maintenance? - empty out the fuel tank, replace the fuel filter (use the NEW type large bodied Stihl), new plug. Grease the clutch bearing, check the drum, hoses, wires, boots etc..
     

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