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2-cycle chainsaw issue... (long)

Discussion in 'The Lounge' started by newyorkin, Aug 23, 2005.

  1. newyorkin

    newyorkin 1 ton status

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    I have a nice handy little 35cc McCulloch chainsaw, bought new last fall. I've probably put about 20-30 hours on it total so far.

    It calls for a 40:1 fuel/oil mix, which I did at first by mixing a big batch and just refilling from that. Now, I do it in much smaller batches, so I'm probably over-oiling it.

    The last two times I've used it, I run into a wierd issue after about an hour or two of running.
    It will lose power badly with more throttle, and the chain will actually stop during cuts. I go WOT, and the saw sputter's and die's or just revs extremely low until I pull it off the load, at which point it sputters and I have to feather it to keep it from stalling.
    If I set the choke half way during this condition, it revs up with throttle, but still loses power as soon as the chain hits something, and barely cuts.

    This first happened last thursday night when I was cutting down a big tree in my yard, so I got all irritated and put it away. I took it out sunday thinking it wouldn't work well at all, and it fired up almost instantly, then cut through the same tree like butter.
    I was happy again, so continued cutting up the tree, and after about an hour or so, the same lost power thing happened. I had filled up on fuel 2x, too.

    The first time it happened, it was a warm day, but not hot. The second time, it was a pretty hot day. So I was thinking maybe it was overheated?? I don't understand how it overheated like that, though. It had plenty of chances to overheat before as I was using it.

    Also, the fuel I used the last two times was premium/high octane (93 I think? I got it when the motorcycle wouldn't start). I would think it would run better with that, but I don't know. My Dodge seems to run better on lower octane...


    So any ideas?
    So should I focus on a cooling issue, defective/damaged engine, or a fuel issue?
     
  2. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    I'm not trying to bust your b@!!s or anything, but the first problem you have is with the saw itself. It's not a quality machine.

    But that's a different story. I'll help you answer your question.

    Do you leave fuel in it when storing?

    It's most likely a small piece of trash blocking the low speed jet.

    Solution, rebuild it or buy a new carb. They're usually cheap, around $25-30 for a new one, and about $10 for the rebuild kit.

    I know the durability periods for McCulloch saws are around 50 hours, as compared to 300 for a Stihl or Shindaiwa. As always, you get what you pay for.

    You should have no problem with the octane fuel you are using. Something many people don't know is that when you add the oil for the mix, it actually reduces the octane rating because it's being diluted.
     
  3. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Ash is right, not a fuel problem. It's a carb problem. Do you have a saw shop near by? Take it in, and let them tune it. I always wanna pull my hair out after messin with a chainsaw carb for any length of time...pain in the ass. And I've never heard of a chainsaw overheating...I've ran 3 gallons of gas through my husqvarna in a day, tank after tank after tank in 100+ degree heat, thing didn't even snort.

    Oh yeah, you should be smacked for buying a McCulloch. :haha:
     
  4. newyorkin

    newyorkin 1 ton status

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    :rotfl: :rotfl:

    I knew I'd catch crap for the brand name... All I knew when buying it was that Stihl is the better brand, but also more $$ than I wanted to spend. I only bought cause it was 70% more than a new chain for my old sears saw...

    Thanks for the direction guys. I'll try to find a shop that can tune/clean it. If their price is more than $40, I'll look at new saw's again. This one was $70, so if it's close to the end of it's usable life anyway, maybe I'll just go get a higher quality saw next.
     
  5. cbbr

    cbbr 1 ton status GMOTM Winner

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    You might also check to make sure that there is nothing floating around in the tank. My weedeater has a filter that gets clogged about once a year. it is small and in the tank. I have to pour the gas out and blow a little air back through the fule line to clear it. If not, I agree that your carb needs to be tuned.
     
  6. newyorkin

    newyorkin 1 ton status

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    BTW, to answer your question, I usually run it out of fuel before putting it away. It sits in storage in my basement with the tank dry.
     
  7. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    You paid $70 for a chainsaw and wonder why it won't work right? What is it...12" bar??? :eek1: ha!

    I think my hurqvarna was close to $700....
     
  8. newyorkin

    newyorkin 1 ton status

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    If you did as much work with a chainsaw as I do, and you spent $700 on one, I'd tell you to get your head examined while I offered to sell you a high quality bridge.
    I wasn't asking "Why is my $70 chainsaw not taking down this 4 foot wide tree after taking down most of the forest?", I was asking "Does anyone have a suggestion on why I'm having an odd mechanical problem before I'm expecting to for the lifespan of the tool?".

    I bought a cheap chainsaw to replace my tired/borrowed Craftsman chainsaw, which is actually smaller. There's no need for you to respond holier than thou. Would you tell a guy with a 30x60' lot and a lawnmower problem that he's a fool because he doesn't have a ride-on with a cup holder?

    If you bought a $200 computer for your business, I'd think you're cheap, but I wouldn't be a bunghole to you. If you bought a $200 computer for internet surfing and emailing, I'd say you spent your money appropriately. I guess we have different ideas of value.


    Since I try not to be rude, to answer your question; it's a 16 inch bar. The biggest tree I'll cut is maybe 16".
     
    Last edited: Aug 23, 2005
  9. surpip

    surpip 1 ton status

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    we had a homelite chansaw, that me granpa bought new, worked great for years and years, last year was its last season in fact
    that thing would probally have ran on kerosene :D
     
  10. newyorkin

    newyorkin 1 ton status

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    Same story with my dad's old craftsman, that thing looks like it was built in 1960 and used every day since...
    I bought this McCulloch when I went to buy a new bar and chain for the Craftsman.
     
  11. Thunder

    Thunder 3/4 ton status

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    Sounds like your carb may be just out of adjustment. There aee 2 screws on the side of it marked H and L. H is for your high speed fuel mixture. To adjust it start it and go to wot Turn the screw out or in till it runs best.
    L is for low speed and acceleration if you have a dead spot when giving the gas. Screw it in or out til it runs right. Mucullochs vibrate a lot and it shakes the screws out of adjustment
    If you cant get it to run right by adjusting the carb. It may be a ignition issue.
    Have you tried a new Spark plug? They can do wonders for a 2 stroke. 2 strokes really like to eat up spark plugs and will run crappy and loose power up on top with a bad plug.
    Try those ideas before taking it to a shop. itll save ya 60 or so $$
     
  12. newyorkin

    newyorkin 1 ton status

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    Cool, thanks. I've seen the L-H markings, but didn't know what they were and saw no adjustable points nearby. Never really looked into the slot, so I'll look again and play with that, and get a spark plug.
     
  13. surpip

    surpip 1 ton status

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    we have a old McCulloch to think weighs a ton, used to be a logging say had a huge bar on it when we got it, took it off and put a 24" bar on it, you dont evan have to lean on it to cut stuff, just let its own weight pull itself through
    but it tears you up when you use it all day :D
    i prefer my bosses Stihl, cuts like a breeze and its super light to
     
  14. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    Haven't seen the exhaust mentioned. It clogs over time due to the burning of oil. A two-stroke has to exhale well to run right. When mine starts acting up, that is the first thing check, and it's clogged twice over the 4 years I have had it. I have my Dad's old 12 inch Homelite I carry up trees hooked to my belt, a Pioneer that was his and a Stil I bought.

    Oh, my Dad logged back in the Thirty's and Forty's with cross cut saws and oxen in the Smoky Mountains. McCullough was his first power saw and used to be the best.
     
  15. 3 on the tree

    3 on the tree 1/2 ton status

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    Have you pulled the sparkplug to see if the rich mixture is fouling it??? FYI the McCulloch name was sold to a Chinese company. I have a Homelite that is 3 years old and has at least 100 hours on it. It's not as good a saw as my old 029 Stihl, but its all I need.
     
  16. jhellwig

    jhellwig 1/2 ton status

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    Unless you know lots about small 2 stroke egines it is best not to mess with anything on the carb. They are very easy to mess up. But if you do want to work on it I would check the diaphram in the carb. Those have a tendancy to go bad and that will do what you are describing. Ethanol will eat them up. Also check the other things that have been mentioned. Theya re all things that can contribute to it.


    If you have easy acces to electricity you might want to try an electric chain saw. I know people that have them and are quite satisfied with them. They will probaly cost less that a mculla and last much longer.
     
  17. Kiwi John

    Kiwi John 1/2 ton status

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    Lots of good thoughts in the help offered so far.
    Do the easy things first, and one at a time.
    The spark plug you need is Champion DJ8J or NGK equivalent(which will be better IMO) Gap at 0.025 - 0.030" CAREFUL: Tapered-seat type plug so only tighten 1/16 - 1/8th turn after hand tight.
    Wash the air filter element in petrol and shake dry then refit.
    Replace the pick-up filter in the tank. They look clean when they are blocked.
    You need a bent coathanger type of hook to pull it up thru the filler hole.
    Set the carb jets both to 1 turn to start with. Screw them in gently till they bottom, then back out 1 turn.
    Start the engine and let it idle (There is a third screw, the throttle stop which is fat and has a pointed end which moves the throttle shaft) Use this screw to keep the engine ticking over at a fast idle.
    Then adjust the L jet to get the fastest idle speed Then back it out (richen the mix) by 1/16th of a turn (i.e. - a little bit) so it slows a bit (helps acceleration from idle).
    Go to WOT and adjust H jet to get the best running.
    It should rev ok and hold power under load.
    If not, something else is wrong and you may have to remove exhaust to clean the carbon build-up in the exhaust port. (piston at BDC for this).
    Last resort - strip the carb, only of you have good eyes and a clean workbench. Parts internally are v.small and get lost easily.
    Do you have ethanol in your fuel there? Not a problem over here but could be affecting the rubber diaphragm as 'jhellwig' says.
    Also there is another fuel filter gauze inside the carb which can block up with dry fuel during storage.
    Best storage technique (IMO) is to keep fuel in the engine and run it up every couple of weeks. same goes for generator and lawnmower.
    Life expectancy for a Mac is approx 70 hours IMO.
    You can only buy what you can afford at the time I think.
    Good Luck.
     
  18. newyorkin

    newyorkin 1 ton status

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    Funny you mention that, my neighbor came over and loaned me his 14" electric when mine started dying 3/4 through a big limb hanging next to his driveway...


    3 on the tree, I had no idea McCulloch was now chinese... I usually avoid product from the People's Republik of China if I can...


    Dontoe, thanks for the exhaust tip, I'll check that too. Come to think of it, I remember there being a lot more exhaust present when I use it than there was last time...
     
  19. newyorkin

    newyorkin 1 ton status

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    Thanks John, I forgot to mention filter had crossed my mind, but I didn't know where it was to get to it.
    Thanks for the detail and storage tips.


    :rotfl:
    It would be funny if the problem was something simple and cheesy, like I just ran a bad batch of fuel through it, then I did all this stuff to it, and had this little thing screaming again...
     
  20. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    My current job was working on small engines, and believe me, I saw plenty of these. If you are able to use it for 2 hours before it cuts off, it's not the exhaust.

    I would also check the fuel first, but I SERIOUSLY doubt it's too rich, and it doesn't have water in it.

    It doesn't sound like a galded cylinder. It wouldn't have run this long.

    Spark sounds good. I doubt it's a coil breaking down either because it continues to run.

    Air filter is good, as is the fuel filter. Again, it wouldn't run that long.

    That's what leads me to believe that it is a piece of trash in the jet.

    Let us know what works.
     

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